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Soc. Sc i . Med . Vol . 24, No. 1 . pp. 71-82 , 1987 027%9536, ,87 $3 ,00 +0 ,00

P r i n te d i n G r e a t B r i ta i n . A l l r i g h t s r e se r v e d C o p y r i g h t ~ 1 9 8 7 P e r g a m o n J o u r n a l s L t d

THE IMPACT OF LATE ADOLESCENT SUBSTANCE

USE ON YOUNG ADULT HEALTH STATUS AND

UTILIZATION OF HEALTH SERVICES: A STRUCTURAL-EQUATION MODEL OVER FOUR YEARS

M ICHAEL D. NEWCOM B an d P . M . BENTLER

Dep ar tm ent o f Psychology , Univers i ty o f Cal i fo rn ia , Los Angeles , C A 90024, U.S .A.

A ~t ra ct - -T his s tudy examined the impact o f ado lescen t substance use on youn g adu l t heal th s tatus andhealth service uti l ization, while contro ll ing for earlier subjective and objective h ealth p roble ms an d seekingmedical care. Data were obtained from 654 participants when they were in late adolescence and 4 yearslater when they were youn g adults. Laten t -var iab le models w ere used to de termine what ef fect , i f any .adolescent drug use had on later health. A s econd -order factor of general drug use had a small , butsignificant, influence on decreasing subjective physical h ardines s over the 4-year period. However, gene raldrug use was not directly related to later physical symptomatology, subjective health problems, or health

service uti l ization. Ge nera l cigarette use an d am ou nt of cigarette sm okin g were significantly related to arange of heal th ou tcomes includ ing increased psychosomat ic symptom s, resp i rato ry symptoms, repor t ingtrouble with health, nights spent in the hospital , and health service uti l ization, as well as decreasedsubjective physical hardiness. Early cann abis use decreased la ter subjective physical ha rdiness an dincreased health problems experienced over the 4 years. Hard drug use was associated with increasedemergency phy sician visits during adolescence a nd increased perceived troub le v, th h ealth as yo ung adults.Due to the fact that adolescent general drug use decreased subjective physical hardiness over 4 years, i tis possible tha t con tinue d substa nce use migh t lead to mo re serious objective h ealth conseq uenc es laterin l ife (i .e. physical symptoms).

T h e u s e o f v a r i o u s d r u g s u b s t a n c e s i s w i d e s p r e a d

a m o n g m o s t s e g m e n t s o f A m e r i c a n s o c ie ty a n d

a m o n g m o s t a g e g r o u p s [ 1 - 3 ]. I n i t i a t i o n i n t o d r u g u s eo c c u r s t y p i c a l l y d u r i n g t h e t e e n a g e y e a r s [ 4] a n d f o r

m a n y b e c o m e s a l i f e s t y l e a f t e r t h a t p e r i o d [ 5 - - 7 ] .

A g r e a t d e a l o f r e s e a r c h h a s b e e n g e n e r a t e d t o

d e t e r m i n e t h e e t i o l o g y o f d r u g - t a k i n g b e h a v i o r s . A

w i d e r a n g e o f p r e d i s p o s i n g f a c t o rs h a v e b e e n

i d e n t i f i e d i n c l u d i n g f a m i l y a n d p e e r m o d e l s [ 8 - 1 4 ] ,

n u m e r o u s t y p e s o f r i s k f a c t o r s [ 15 , 1 6 ] , d e v i a n c e ,

p r o b l e m b e h a v i o r , o r l a c k o f s o c ia l c o n f o r m i t y

[9, 1 7 , 1 8 ] , l o w se l f - es t eem , d ep re ss io n , o r p sy c h o -

l o g i ca l d i s t r es s [1 9 ,2 0 ] , a n d s t r es s fu l li f e ch a n g e

events [21 , 22] .

D e s p i t e t h i s p l e t h o r a o f r e s e a r c h o n t h e c a u s e s o f

d r u g u s e , t h e r e i s l i t t l e r e s e a r c h o n t h e c o n s e q u e n c e s

o r o u t c o m e s o f s u b s t a n c e u s e a m o n g a d o l e s c e n t s . I t

i s c r u c i a l to d e t e r m i n e w h e t h e r s o c ia l , e m o t i o n a l , a n d

p h y s i c a l d e t e r i o r a t i o n m a y o c c u r a s a r e s u l t o f s u b -

s t a n c e u s e d u r i n g t h e t e e n a g e y e ar s . T h i s i n f o r m a t i o n

w i ll h e lp u s t o u n d e r s t a n d b e t t e r t h e i n d i v i d u a l a n d

s o c ie t a l i m p a c t s a n d c o s ts o f d r u g t a k i n g b e h a v i o r s

[231.T h e p h y s i c a l d e t e r i o r a t i o n e f f e c ts o f e x c e s si v e u s e

o r a b u s e o f v a r i o u s d r u g s u b s t a n c e s h a v e b e e n w e l l

d o c u m e n t e d . I n f a ct , M a t a r a z z o [2 4] c o n s i d e r s d r u g

u s e i ts e l f a s i g n i f i c a n t h e a l t h p r o b l e m o f n a t i o n a l

c o n c e r n . I n r e g a r d t o s p e ci f ic s u b s t a n c e s , t h e p h y s -

i ca l l y d es t ru c t i v e e f f ec t s o f a l co h o l ab u se [25 , 2 6 ],

e x c e s s iv e m a r i j u a n a u s e [ 27 , 2 8] , c i g a r e t t e s m o k i n g[ 29 , 3 0] , a n d m o r e r e c e n t l y c o c a i n e a b u s e a n d a d d i c -

t i o n [ 3 1 ] , a r e b e c o m i n g e s t a b l i s h e d s c i e n t i f i c a l l y .

H o w e v e r , t h i s r e s e a r c h h a s f o c u s e d l a r g e l y o n o l d e r

s a m p l e s w i t h l e n g t h y d r u g a b u s e c a r ee r s . I t h a s n o t

71

b e e n e s t a b l i s h e d w h e t h e r t e e n a g e d r u g u s e o v e r a

r e l a t i v e l y s h o r t p e r i o d o f t i m e l e a d s t o s e v e r e h e a l t h

c o m p r o m i s e s . I n h e a l t h y p e o p l e [ 3 2 ] , t h e s h o r t - t e r mh a z a r d s o f d r u g u s e o n a d o l e s c e n t h e a l t h a r e c o n -

s i d e r e d s e c o n d a r y e f f e c t s ( s u c h a s i n c r e a s e d r i s k o f

t r a f f i c a c c i d e n t s ) , r a t h e r t h a n p r i m a r y e f f e c t s o f t h e

d r u g u s e i t s e l f . I t i s p o s s i b l e , h o w e v e r , t h a t m o d e r a t eo r e v e n e x p e r i m e n t a l s u b s t a n c e u s e o v e r a r e l a t i v e ly

b r ie f d u r a t i o n a m o n g a d o l e sc e n t s m a y d i s r u p t a n d

i n t e rf e r e w i t h n o r m a l g r o w t h p a t t e r n s d u r i n g t h e

c r u c i a l m a t u r a t i o n a l p e r io d o f p u b e r t y a n d t h e y e a r s

f o l l o w i n g a n d r e s u l t i n p r i m a r y e f f ec ts o f s u b s t a n c e

u s e. I n o t h e r w o r d s , t e e n a g e r s m a y b e m o r e a t r is k f o r

p h y s i c a l h e a l t h d e t e r i o r a t i o n a s a r e s u l t o f d r u g u s e

t h a n o l d e r a d u l t s w h o s e p h y s i c a l d e v e l o p m e n t a n d

m a t u r i t y a r e m o r e f u ll y e s t a b l is h e d .

I n o n e s t u d y , v e r y l it t le p h y s i c a l d e t e r i o r a t i o n w a s

f o u n d i n a g r o u p o f a d o l e s c e n t a l c o h o l a b u s e r s [ 3 3].

C a s e s b f 34 t e e n a g e r s w h o w e r e a d m i t t e d t o t h e

A d d i c t i o n R e s e a r c h C e n t e r f o r a l c o h o l a b u s e w e r e

r e v ie w e d . I t w a s c o n c l u d e d t h a t p h y s i c a l s y m p t o m s o f

a l c o h o l d e p e n d e n c e ( d e l i r i u m t r e m e n s , l i ve r d a m a g e )

w e r e q u i t e r a r e . C h a s s i n [ 3 4 ] p o i n t s o u t t h a t t h e

" n o t i o n s o f p h y s i c a l a d d i c t i o n ( s u c h a s w i t h d r a w a l

s y m p t o m s ) o r s e r i o u s p h y s i o l o g i c a l d e t e r i o r a t i o n ,

w i ll be i n a p p r o p r i a t e t o d e f i n i n g d r u g a b u s e w i t h i n

a n a d o l e s c e n t s a m p l e " ( p . 1 28 ). O n t h e o t h e r h a n d ,

t e e n a g e d r u g u s e m a y h a v e i m p l i c a t i o n s fo r l o n g - t e r m

a d u l t h e a l t h o u t c o m e s t h r o u g h t h e e s t a b l i s h m e n t o f

h a b i t u a l b e h a v i o r s a s s o c i a t e d w i t h c h r o n i c h e a l t hr is k s s u c h a s c ig a r e t te s m o k i n g , p o o r d i e t , a n d o t h e r

l i f e s ty l e imb a l an ces [3 4 , 3 5 ] .

C o m p l i c a t i n g t h e s e is s u e s is t h e f a c t t h a t m o s t

t r e a t e d a d o l e s c e n t d r u g a b u s e r s [ 3 6 ] a n d m a n y t e e n -

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7 2 M I C H A E L D . N E W C OM B a n d P . M . B E N TL E R

a g e u s e r s in t h e g e n e r a l p o p u l a t i o n [ 3 7 ] a r e p o l y d r u g

u s e r s , w h i c h m a k e s i t d i f f i c u l t t o d o c u m e n t p h y s i c a l

s y m p t o m s r e l a t e d t o d r u g u s e o r a n y s p e c if ic s u b -

s t a n c e [ 38 ]. H o w e v e r , i n o u r a n a l y s e s p r e s e n t e d i n t h i s

p a p e r , t h e u s e o f l a t e n t - v a r i a b l e s tr u c t u r a l m o d e l s

a l l o w s u s t h e f l e x i b i l it y t o t e s t f o r e f f e c t s o f g e n e r a ld r u g u s e , a s w e l l a s , s p e c if i c s u b s t a n c e s i n a s i m u l -

t a n e o u s m a n n e r .A r e c e n t s tu d y [ 3 9 ] a t t e m p t e d t o d e t e r m i n e t h e

i m p a c t o f v a r i o u s t y p e s o f d r u g u s e o n c h a n g e i n

h e a l t h s ta t u s f r o m a d o l e s c e n c e t o y o u n g a d u l t h o o d .

T h e y r e p o r t e d t h a t u s e o f i n h a l a n t s , h e r o in , a n d

m e t h a d o n e w a s a s s o c i a t e d w it h h e a l t h d e t e r i o r a t i o n

o v e r t h e i r 7 - y e a r l o n g i t u d i n a l s t u d y o f b l a c k y o u t h .U n f o r t u n a t e l y , t h e s e r e s u l t s a r e p r o b l e m a t i c d u e t o

s e v e r al d e s ig n a n d m e t h o d o l o g i c a l i s su e s. F i r s t , m o s td r u g u s e a ss e s s m e n t s w e r e o b t a i n e d a t t h e f o l l o w - u p

i n t e r v i e w a n d c a n n o t a c c u r a t e l y r e f l e c t u s e 7 y e a r s

e a r l i e r . S e c o n d , s u p p r e s s o r e f f e c t s w e r e e v i d e n t i nt h e i r r e g r e s s i o n e q u a t i o n s , s u g g e s t i n g c o l i n e a r i t i e s i n

t h e i r d a t a r e q u i r i n g a d d i t i o n a l a n a l y s e s ( t h a t w e r en o t p e r f o r m e d ) p e r h a p s u t i l iz i n g a l a t e n t - v a r i a b l e

m e t h o d ( w h i c h c o u l d t a k e a d v a n t a g e o f th e h i g h

c o r r e l a t i o n s b y f o r m i n g a l a t e n t c o n s t r u c t ) . F i n a l l y ,t h e a d o l e s c e n t h e a l t h m e a s u r e w a s t h e o n l y v a r i a b l e

a c t u a l l y a s s e s s e d d u r i n g a d o l e s c e n c e ( i n a d d i t i o n t oc i g a r e t t e u s e ) , a n d d u e t o b e i n g p o o r l y d e s c r i b e d , i t

i s i m p o s s i b l e t o d e t e r m i n e i t s s i m i l a r i t y o r d i f f e r e n c et o t h e f o l l o w - u p h e a l t h m e a s u r e . T h e s e p r o b l e m s

r a i s e s e r i o u s d if f i c u lt i e s w i t h t h i s s t u d y a n d m a k e

i n t e r p r e t a t i o n o f t h e d a t a d i ff i cu l t.

O n e o f t h e m o s t w i d e l y r e s e a r c h e d d r u g s i n t e rm s

o f c o n s e q u e n c e s h a s b e en a l c o h o l a m o n g a d u l t

s a m p l e s ( p r o b a b l y s e c o n d o n l y t o c i g a r e t t e s m o k i n g ) .

F o r i n st a nc e , G o r d o n a n d K a n n e l [ 4 0 ] f o u n d t h a td r i n k e r s h a d l o w e r m o r t a l i t y th a n n o n - d r i n k e r s ( o v e r

a p e r i o d o f 2 2 y e a r s ) a n d l i g h t d r i n k e r s h a d t h e l o w e s t

m o r t a l i t y . T h e r e w a s a s t r o n g a s s o c i a t i o n b e tw e e n

h e a v y d r i n k i n g a n d s t o m a c h c a n c e r . M o s t o t h e r

s t u d i e s h a v e r e p o r t e d h i g h e r m o r t a l i t y f o r h e a v y

a l c o h o l u s e r s [ 4 1 , 4 2 ] . O n t h e o t h e r h a n d , R i c h m a na n d W a r r e n [ 4 3 ] f o u n d a n a p p a r e n t b e n e f ic i al ef fe c t

o f b e e r ( s p e c i f ic a l l y ) o n g o o d h e a l t h s t a t u s . U n -

f o r t u n a t e l y , t h e y d i d n o t c o n t r o l f o r i n i t i a l b a s e l i n e

o f p o o r h e a l t h . T h e s e r e s u l ts s u g g e st t h a t s o m e t y p e s

o f d r u g u s e m a y h a v e b e n e f i c i a l e f f e ct s , a n d t h a t

w e m u s t l o o k f o r p o s s i b l e h e a l t h e n h a n c i n g o u t c o m e s

o f s u b s t a n c e u s e , a s w e l l as , p o s s i b l e d e t e r i o r a t i o neffects .

I n t h i s s tu d y , a s s e s s m e n t s o f d r u g u s e t a k e n d u r i n gl a t e a d o l e s c e n c e a r e u s e d t o p r e d i c t h e a l t h s t a t u s

( s u b j e c t i v e a s s e s s m e n t s a n d s y m p t o m r e p o r t s ) a n dh e a l t h s e r v i c e u t i l i z a t i o n 4 y e a r s l a t e r a s y o u n g a d u l t s .L e v e ls o f p o o r h e a l t h a n d m e d i c a l c a r e u t i l i z a t i o nd u r i n g a d o l e s c e n c e a r e c o n t r o l l e d i n o r d e r t o e s t a b -l i s h w h e t h e r d r u g u s e a c t u a l l y l e a d s t o c h a n g e s i np h y s i c a l h e a lt h o v e r t i m e . L a t e n t - v a r i a b l e s t r u c t u r a lm o d e l s a r e u s e d t o t e s t t h e s e h y p o t h e s i z e d a s s o c i -a t i o n s . I n o r d e r n o t t o b i a s o u r r e s u l t s , w e h a v e

c h o s e n a c o n s e r v a ti v e a p p r o a c h t o a n a l y z i n g o u rd a t a . T h i s a p p r o a c h e n t a i ls a ll o w i n g m o s t c o n s t r u c t s

o r v a r i a b l e s a t o n e t i m e p o i n t t o s i m p l y c o r r e l a t e a n dn o t i m p o s e a n y c a u s a l o r d e r w i t h i n t i m e . A s a r e s u lt ,t h e e f f e c t s o f d r u g u s e o n h e a l t h w i l l o n l y b e a c r o s st i m e , w i t h s t a b i l i t y e f f e ct s a n d p r i o r h e a l t h v a r i a b l e s

c o n t r o l l e d .

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A s p a r t o f a n 8 - y e a r ( fi ve w a v e ) s t u d y o f a d o l e s c e n t

a n d y o u n g a d u l t d r u g u s e a n d d e v e l o p m e n t , 6 5 4i n d i v i d u a l s p r o v i d e d d a t a a s o l d e r a d o l e s c e n t s (w a v e

4 ) , a n d a g a i n a s y o u n g a d u l t s 4 y e a r s l a t e r ( w a v e 5 ) .

T h e s t u d y o r i g i n a l l y b e g a n w h e n a l l s u b j e c t s w e r e int h e s e v e n t h , e i g h t h , o r n i n t h g r a d e s i n L o s A n g e l e sC o u n t y . A t t h a t ti m e 1 6 3 4 s t u d e n t s a g e e d t o p a r -t i c i p a t e : 3 6 % w e r e m a l e a n d 6 4 % w e r e f e m a l e . W e

a r e u s i n g o n l y t h e l a s t t w o w a v e s o f d a t a , s i n c e t h e se

w e r e t h e o n l y o c c a s i o n s t h a t d e t a i l e d h e a l t h a s s e s s -

m e n t s w e r e o b t a i n e d . A d e s c r i p t i o n o f th i s sa m p l e a s

y o u n g a d u l t s i s g i v e n i n T a b l e 1 .S e v e n t y p e r c e n t o f t h e p r e s e n t s a m p l e a r e f e m a l e

a n d 3 0 % a r e m a l e . B r e a k d o w n s b y o t h e r d e m o -

g r a p h i c c h a r a c t e r i s t i c s s u c h a s i n c o m e , l i f e p u r s u i t ,

e t h n i c it y , a n d l iv i n g a r r a n g e m e n t s a r e a l s o p r o v i d e di n T a b l e 1 . A t a l l s t a g e s o f t h e s t u d y , p a r t i c i p a n t s

w e r e i n f o r m e d o f a g r a n t o f c o n f id e n t i a l i ty gi v en b yt h e U . S . D e p a r t m e n t o f J u s ti c e w h i c h l e g a l ly p r o t e c t s

t h e i r r e s p o n s e s . E a c h r e s p o n d e n t a t t h e y o u n g a d u l tf o l l o w - u p w a s p a i d $ 1 2 .5 0 f o r t h e i r p a r t i c i p a t i o n .

A n e x t e n s i v e s e r i e s o f a t t r i t i o n a n a l y s e s , r e p o r t e do n e l s e w h e r e [ 44 , 4 5 ], r e v e a l e d t h a t p a t t e r n s o f d r o p -

p i n g o u t o f t h e s t u d y w e r e o n l y s l i g h t ly sy s t e m a t i cd u e t o d r u g u s e , p e r s o n a l i t y , o r g e n d e r o f t h e re -

s p o n d e n t . T h u s , a l t h o u g h t h e r e t e n t i o n r a t e a f t e r 8

T a b l e 1 . D e s c r i p t i o n o f s a m p l e

N u m b e r o f P e r c e nt

V a r i a b l e s u b j e c ts o f s a m p l e

T o t a l 6 5 4 1 0 0

Sex:M a l e 1 9 2 2 9

F e m a l e 4 6 2 7 1

A g e :21 253 392 2 2 1 4 3 3

23 170 2624 17 2

E t h n i c i t y :B l a c k 9 7 1 5

H i s p a n i c 6 4 1 0W h i t e 4 3 2 6 6

A s i a n 6 1 9

Cu r r e n t l i f e a c t i v i t y :M i l i t a r y 1 7 3

J u n i o r c o l l e g e 7 9 1 2U n i v e r s i t y 1 3 9 2 1

Pa r t - t i m e j o b 8 9 14 .Fu l l - t i m e j o b 3 0 5 4 7N o n e 2 5 4

I n c o m e l a s t y e a r :N o n e 6 2 9

L e s s t h a n $ 5 0 0 0 2 1 5 3 3B e t w e e n $ 5 0 0 0 a n d $ 1 5 , 0 00 3 0 0 4 6O v e r $ 1 5 ,0 0 0 7 6 1 2

C u r r e n t l i v i n g a r r a n g e m e n t s :A l o n e 2 7 4W i t h p a r e n t ( s ) 3 1 1 4 8

Sp o u s e 6 8 1 0S p o u s e a n d c h i l d (r e n ) 4 3 7C o h a b i t a t i o n 5 8 9D o r m i t o r y 3 7 6W i t h r o o m m a t e s 8 1 1 2O t h e r 2 9 4

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A d o l e s c e n t d r u g u s e a n d y o u n g a d u l t h e a l t h s t a tu s 7 3

years was 45%, not surprising considering the nature

and length of the research, results should not be

gravely biased due to subject loss.In order to determine the representativeness of our

remaining 654 individuals, we compared our sampleto other nationa l samples and to individuals in

studies similar to ours. When characteristics (e.g.

income, living arrangements, etc.) of our participantswere compared to United States national surveys ofyoung adults [2, 3] and other samples of young adults

[5, 11] very similar patterns were noted. Our group ofyoung adults did not appear to be markedly different

from young adults in the United States. The main

difference was that our sample had a greater per-centage of women than men (and has had since its

beginning).Finally, we compared report ed drug use between

our sample and a national representative sample of

young adults [2]. Prevalence levels were equal on

hallucinogens, heroin, sedatives, analgesies, and

cigarettes, whereas our sample reported significantlyhigher prevalence for use of cannabis, cocaine, stim-

ulants, tranquillizers and alcohol. Clearly. we havenot lost substantial numbers of drug users as a result

of attrition.

Measures

Thirty-one measured variables are used to reflect

ten primary-order latent constructs. One variable.

physical symptom index, is not used as an indicatorof a factor and is considered at the level of a latent

construct, al though it is a manifest variable. This wasdone in order to make separate variables for ado-

lescent health status: an objective assessment (phys-

ical symptom index) and a subjective or perceived

assessment (subjective poor health). In young adult-hood, there are two subjective health constructs

(subjective physical hardiness and subjective poorhealth) and one for objective health status (physical

symptomatology).A sum mary of va riable characteristics for these 31

measures is provided in Tab le 2. Table 2 is organized

into the initial hypothesized factor groupings of theten latent constructs. Six latent factors and the phys-

T a b l e 2 . S u m m a r y o f v a r i a b l e c h a r a c t e r i s t ic s

P o i n t - b i s e r i a l

c o r r e l a t i o n s e x

V a r i a b l e M e a n R a n g e V a r i a n c e S k e w K u r t o s i s d i ff e re n c e *

L a t e a d o l e s c e n c e

C i g a r e t t e u s e :

C i g a r e t t e f r e q u e n c y 2 . 4 3 I - 7 4 . 8 4 1 . 3 l 0 . 0 7 0 .0 6~ "

Cig are t t e qu an t i t y 1 .55 1 -7 1 .28 2 .51 6 .40 0 . I I**

A l c o h o l u s e :

B e e r f r e q u e n c y 2 . 7 9 1 - 7 . 2 . 6 6 0 . 35 - 1 . 2 7 - 0 . 1 8 §

W i n e f r e q u e n c y 2 . 3 2 I - 7 1 .6 0 0 . 63 - 0 . 6 7 0 . 08 +L i q u o r f r e q u e n c y 2 . 3 9 I - 7 1 .9 9 0 . 65 - 0 . 7 5 - 0 . 0 3

C a n n a b i s u s e :

M a r i j u a n a f r e q u e n c y 2 . 42 I - 7 3 .4 1 1 .0 2 - 0 . 3 4 - 0 . 0 4

H a s h i s h f r e q u e n c y 1 .5 3 I - 7 1 .1 6 2 . 1 9 4 . 1 4 - 0 . 0 4

H a r d d r u g u s e :

S e d a t i v e f r e q u e n c y 1 .0 7 I - 7 0 . 4 7 6 . 6 2 5 3 . 8 6 0 . 0 2

S t i m u l a n t f r e q u e n c y 1 .1 6 1 - 7 0 . 6 7 3 . 2 3 1 2 .9 3 0 .0 4

P s y c h e d e l i c f r e q u e n c y 1 .0 9 I - 7 0 .3 1 5 . 7 0 4 1 . 5 8 0 . 0 0

S u b j e c t i v e p o o r h e a l t h :

Tim es fe l t rea l l y s i ck 1 .55 0 - 6 2 .28 1 .31 1 .41 0 .15 ,}

I l ln e s s s e n s i ti v e 9 . 6 3 4 - 2 0 1 5 , 2 8 0 . 5 6 - 0 . 3 7 0 . 1 6~

P h y s i c a l s y m p t o m i n d e x 4 . 0 5 0 - 2 5 9 .6 1 0 .9 9 0. 81 0 . 13 ~

H e a l t h s e r r i c e u t i l i z a t i o n :

N i g h t s i n h o s p i t a l 0 . 1 5 0 - 6 0 . 5 0 6 . 4 2 4 4 . 7 2 0 . 01

T i m e s s e e n p h y s i c i a n f o r e m e r g e n c y 0 . 2 8 0 - 6 0 . 5 5 4 . 07 2 1 . 53 0 . 0 0

T im es seen phy s i c i a n fo r i l l nes s 0 .83 I )- -6 1 .75 2 .08 4 .60 0 .13~

Y o u n g a d u l t h o o d

S u b j e c t i c e p h y s i c a l h a r d i n e s s

No t res i s t a n t t o i l l nes s 2 .33 1 -5 2 .21 0 .71 0 .14 0 .17§

H e a l t h w o r s e t h a n e a r l i e r 1 .8 8 1 - 5 1 .6 9 0 . 9 9 0 . 3 2 0 . 10 " .

V e r y h a r d y 3 . 78 1 - 5 1 .7 3 - 0 . 9 5 0 . 5 5 - 0 . 1 ~

I l ln e s s s e n s i ti v e 9 . 2 5 4 - 2 0 1 4 .2 5 0 .6 1 - 0 . 3 0 0 . 1 7 §

S u b j e c t i r e h e a l t h p r o b l e m s :

H a p p y w i t h h e a l t h 5 . 6 2 I - 7 1 .3 9 - 1 .2 3 2 . 0 2 - 0 . 0 7

H e a l t h p r o b l e m s p a s t 4 y e a r s 0 . 1 3 0 - 4 0 . 2 5 4 . 7 6 2 5 . 8 0 0 . 0 3

H a v e t r o u b l e w i t h h e a l t h 1 .5 6 1 - 5 0 . 7 5 - 1 , 8 3 3 . 5 8 0 . 1 7 §

P h y s i c a l s y m p t o m a t o l o g y :

R e s p i r a t o r y s y m p t o m s 1 .9 3 0 - 1 1 3 . 8 3 1 ,4 3 2 . 3 8 0 . 0 3

P s y c h o s o m a t i c s y m p t o m s 3 . 7 5 0 - 1 5 7 . 9 9 0 , 9 5 0 . 8 2 0 .2 1~

S e i z u r e s y m p t o m s 0 . 4 9 0 - 6 0 . 6 9 2 ,1 1 5 . 8 0 0 . I0 ~ .

Tim es fel t rea l ly i l l 1 .29 0--6 1.91 1,44 2.19 * 0.13§

H e a l t h s e r e ' i c e u t i l i z a t i o n :

Tim es seen phy s i c i a n fo r i l l nes s 0 .79 0 - -6 1 .56 2 ,19 5 .42 0 .16~Nig h t s i n hos p i t a l 0 .11 0 - -6 0 .30 7 .05 59 .37 0 .10~.

H o s p i t a l i z a t i o n s p a s t 4 y e a r s 0 . 2 6 0 - 4 0 . 2 8 2 .1 3 5 . 4 6 0 . 0 9 ~

T i m e s s e e n p h y s i c i a n f o r e m e r g e n c y 0 . 2 6 0 - -6 0 . 5 0 3 , 7 5 1 8 . 2 5 0 . 0 9 5

* A p o s i ti v e c o r r e l a t i o n i n d i c a t e s th e w o m e n h a d t h e l a r g e r v a l ue .

~ ' P <0 . 0 5 ; ~ P < 0 . 0 1 ; § P < 0 . 0 0 1 .

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74 MICHAEL D. NEWCOMB and P. M. BENTLER

ical s~mptom index were from the adolescent data

and four latent constructs were from the young adult

follow-up.

D rug use . Adolescent drug use measures included

frequency of use during the past 6 months for 22

different substances and one quantity assessment ofcigarette consumption. Frequency responses were

given on a seven-point anchored rating scale thatranged from never use (1) to more than once per day

(7). Two measures were used to reflect a latent

construct of cigarette use: cigarette frequency andcigarette quantity. The cigarette quantity measure

was rated on a seven-point scale that ranged from

none (1) to more than two packs per day (7). Beer,

wine, and liquor frequency of use variables were

selected to reflect a latent construct of alcohol use.Mar iju ana and hashish frequencies were selected to

represent a cannabis use latent factor. The 15 hard

drug use variables were factor analyzed and averaged

into three scales reflecting a latent construct of hard

drug use. The three scales included stimulants (an

average of five substances such as amphetamines,cocaine, and inhalants), sedatives (an average of

seven substances such as barbiturates, tranquillizers,and narcotics), and psychedelics (an average of three

substances including LSD, other psychedelics, and

PCP). Although among older, adult samples, the use

of sedative-type substances is not considered hard

drug use, ingestion of such substances for non-

medical purposes by adolescents is considered quite

deviant and is considered hard drug use [46, 47].

S u b j e c t i v e p o o r h e a l th . Two measures were used toreflect a construct of subjective poor health status

during adolescence. These included times felt really ill

[rated for the past 6 months on a seven-point an-chored scale that ranged from none (0) to six times

or more (6)] and illness sensitive (a sum of four bipol ar

rati ng scales tha t assessed perce ived vulne rabi lity or

sensitivity to illness, taken from the Bent ler Medical-

Psychological Inventory [48]).

P h y s i c a l s y m p t o m i n d e x. A single, multi-item indi-

cator was used to reflect an objective measurement of

adolescent health status, the physical symptom index.This index consists of a sum of the presence (1) or

absence (0) of 25 physical symptoms such as frequent

headaches, wheezing, allergies, tightness in chest,

high blood pressure, frequent consti pation, and shake

or tremble.H eal t h s e rv i ce u t i l i za t i on , ado l e scence . Three items

were used to reflect a latent factor of health service

utilization during adolescence. These items includedtimes seen physician for illness, times seen physician

for emergency, and nights spent in the hospital. Eachof these items was rated for the past 6 months on aseven-point rating scale that ranged from none (0) tosix or more times (6). These measures were obtained

from a sourcebook for assessing consequences of

marijuana use [49].Sub j ec t i ve phys i c a l hard i nes s . Four scales were used

to reflect a factor of subjective physical hardiness (or

lack of perceived susceptibility to disease) during

young adulthood. Three variables have reversed fac-tor loadings since they measure sensitivity to illnessor lack of hardiness. The illness sensitive variable isthe same measure used during adolescence from theBentler Medical-Psychological Inventory [48]. The

other three scales were derived from seven items thatassessed relative resistance to illness [49]. Each item

was rated on a five-point anchored scale ranging

from definitely false (1) to definitely true (5). Theseven items were factor analyzed using a maximum

likelihood method and an oblique factor rotation.

Three correlated factors were found. These factors

included not resistant to illness (three items: seem toget sick easier than others; most people get sick easier

than I do [negative loading]; and when there issomething going around, I usually catch it), health

worse than earlier (two items: not as healthy now as

I used to be; and I am somewhat ill), and very hardy

(two items: body seems to resist illness very well; andhealth is excellent). Items within each factor were

averaged.S u b j e c t i v e h e a l t h p r o b l e m s . Three variables were

used to reflect a factor of subjective health problems.

Happy with health was assessed with a single itemthat asked the respondent to indicate their amou nt of

happiness with their health on a seven-point ratingscale that ranged from terrible (l) to delighted (7).Health problems past 4 years was created by sum-

ming four dichotomous variables that asked thesubject whether they had had major health problems

during each of the 4 years preceding the current

assessment. Each item was scored '0' if they did not

report a problem for a particular year and a '1' if a

problem was reported. Have trouble with health was

measured by a single item that asked the subject to

rate their amount of difficulty experienced with their

health on a five-point scale that ranged from nodifficulty (1) to extreme difficulty (5).

P h y s i c a l s y m p t o m a t o l o g y . Each respondent indi-

cated how frequently they had experienced each of 22physical symptoms on a three-point rating scale thatranged from not at all (0) to a lot (2). These items

were developed by a physician and were taken from

the marijuana consequences sourcebook [36]. These

22 items were factor analyzed using a maximumlikelihood method with oblique factor rotation.

Three clear factors emerged that included respiratorysymptoms (seven items such as sore throat, wheezing,

coughing spells, and shortness of breath), psycho-somatic symptoms (11 items such as headaches,

trouble falling asleep, and skin problems), and seizure

symptoms (four items such as dizzy spells, con-

vulsions, and passed out). Items were summed intothese three scales. A fourth variable was also included

to represent physical symptomatology. This item

assessed the number of times the subject felt really

sick during the past 12 months. Responses wereindicated on a six-point anchored scale that ranged

from none (0) to six or more times (6).H eal t h s e rv i ce u t i l i za t i on . Four variables were used

to determine the frequency of physician and hospital

visits. Three single items assessed num ber of nights inhospital, times seen physician for an emergency, and

times seen physician for an illness. These were as-sessed in the same manner as the three health service

utilization variables during adolescence. In addition,

four dichotomous items were used to determine thenumber of hospitalizations during the past 4 years.For each of the 4 years preceding the young adultassessment the subject indicated whether they hadspent at least one night in the hospital. If they had not

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Adolescen t d rug use and young adu l t hea l th s ta tus 75

b e e n i n th e h o s p i t a l d u r i n g a p a r t i c u l a r y e a r t h e y w e r e

s c o r e d ' 0 ' a n d t h e y w e r e g i v e n a ' 1 ' i f t h e y h a d . T h e s e

f o u r i t e m s w e r e s u m m e d .

A n a l y s e s

F i r s t , s e x d i f f e r e n c e s a r e e x a m i n e d f o r t h e 3 1

m e a s u r e d v a r i a b l e s . P o i n t - b i s e r i a l c o r r e l a t i o n s a r e

u s e d t o t e s t f o r t h e s e m e a n d i f f e r e n c e s , s i n c e t h e s e a r em a t h e m a t i c a l l y e q u i v a l e n t t o t - t e s t s , w i t h t h e a d d e d

a d v a n t a g e o f p r o v i d i n g t h e a m o u n t o f v a ri a n c e ac -

c o u n t e d f o r b y t h e m e a n s ex d if f e r e n c e w h e n s q u a r e d .

N e x t , a c o n f i r m a t o r y f a c t o r m o d e l o f t h e t e n la t e n t

c o n s t r u c t s i s t e s t e d a n d r e f i n e d . F i n a l l y , a s e ri e s o f

s t r u c t u r a l - e q u a t i o n m o d e l s a r e t e s t e d t o d e t e r m i n e

t h e i m p a c t o f a d o l e s c e n t d r u g u s e o n y o u n g a d u l t

h e a l t h m e a s u r e s , w h i l e c o n t r o l l i n g f o r a d o l e s c e n t

h e a l t h p r o b l e m s a n d h e a l t h c a r e u t i l i z a t i o n . L a t e n t -

v a r i a b l e s t r u c t u r a l m o d e l s w e r e s e l e c t e d t o p e r f o r m

o u r a n a l y s e s s i n c e t h e y h a v e s e v e r a l d i s t i n c t a d v a n -

t a g e s o v e r t y p ic a l o b s e r v e d o r m a n i f e s t v a r i a b l e t y p e s

o f a n a ly s e s , s u c h a s m u l t i p l e r e g r e s s io n . T h e m o s tn o t e w o r t h y a d v a n t a g e i s t h a t r e l a t i o n s h i p s a r e t es t ed

a m o n g e s s e n t ia l l y e r r o r - f r e e c o n s t r u c t s. T h i s i s a c -

c o m p l i s h e d b y s e p a r a t i n g t r u e - s c o r e v a r i a t i o n ( t h e

s h a r e d p o r t i o n o f t he v a r i a n c e a m o n g h y p o t h e si z e d

i n d i c a t o r s ) f r o m e r r o r s o f m e a s u r e m e n t . A s a re s u lt ,

t h e a s s o c i a t i o n s n o t e d t e n d t o b e m o r e p o w e r f u l a n d

d i s a t t e n u a t e d b y e r r o r . O t h e r a d v a n t a g e s i n c l u d e th e

s i m u l t a n e o u s t e st o f l a r g e h y p o t h e s i z e d m o d e l s t h a t

c a n i n c l u d e c o n t r o l v a r i a b l e s , s t a b i l i t y e f f e c t s , a n d

i n f l u e n c e s a t v a r i o u s l e v e l s o f a b s t r a c t i o n ( i .e . fi r st

a n d s e c o n d o r d e r c o n s t r u c t s , o b s e r v e d v a r i a b l e s ) , a s

w e l l a s d i r e c t t e s t s o f h y p o t h e s i z e d m o d e l s i n a n e s t e d

fa s h io n [5 0 , 5 1 ] .

T h e d a t a a r e r a t h e r n o n - n o r m a l b o t h u n i v a r ia t e l y( s e e T a b l e 2 ) a n d m u l t i v a r i a t e l y ( n o r m a l i z e d m u l t i -

v a r i a t e k u r t o s i s e s t i m a t e = 1 6 7. 4 7) . B e c a u s e o f t h e s e

d i s t r i b u t i o n a l p r o b l e m s , i t w o u l d b e p r e f e r a b l e t o u se

a d i s t r i b u t i o n - f r e e m e t h o d f o r m o d e l e s ti m a t i o n

[ 52 , 5 3] , h o w e v e r , d u e t o t h e s i z e o f t h e m o d e l t h i s i s

n o t p o s s i b l e [ 5 4 ] . T h e m a x i m u m l i k e l i h o o d e s t i m a t o r

w i l l b e u s e d f o r i n i t ia l m o d e l s a n d n e e d e d m o d i f i -

c a t i o n s , w h i c h h a s p r o v e n t o b e r e a s o n a b l y r o b u s t

o v e r n o r m a l i t y v i o l a t i o n s [5 5]. T h e E Q S s t r u c t u r a l

e q u a t i o n s p r o g r a m i s u s e d f o r t h e l a t e n t -v a r i a b l e

a n a ly s e s [5 6 ] .

RESULTS

S e x d i f f e r e n c e s

P o i n t - b i s e r i a l c o r r e l a t i o n s w e r e u s e d t o t e s t f o r

m e a n d i f f e r e n c e s o n t h e 3 1 o b s e r v e d v a r i a b l e s b e -

t w e e n m e n ( s c o r e d 1 ) a n d w o m e n ( s c o r e d 2 ). T h e s e

t e st s a re p r e s e n t e d i n T a b l e 2 . M e n r e p o r t e d m o r e

b e e r , l es s w i n e , a n d l e ss c i g a r e t t e u s e t h a n w o m e n . N os e x d i f f er e n c e s w e r e a p p a r e n t o n t h e c a n n a b i s o r h a r d

d r u g u s e v a r i a b l e s. O n t h e m a j o r i t y o f t h e h e a l t h

s t a t u s a n d u t i l i z a t i o n v a r i a b l e s , w o m e n r e p o r t e d

s i g n i fi c a n t ly p o o r e r h e a l t h a n d g r e a t e r u s e o f m e d i c a l

s e r v ic e s t h a n m e n . H o w e v e r , t h e se d i f fe r e n c es w e r e

r e l a t iv e l y sm a l l , a c c o u n t i n g f o r a t m o s t 4 % o f t h e

v a r i a n c e b e t w e e n m e n a n d w o m e n .

E a r l i e r s c a l i n g a n d f a c t o r a n a l y s e s o f t h e h e a l t h

m e a s u r e s c o n f i r m e d t h a t t h e f a c t o r s t r u c t u re s f o r m e n

a n d w o m e n w e r e q u i t e s i m i l a r [ 5 7 ] . D u e t o t h e s m a l l

s e x d i f f e r e n c e s o n i n d i v i d u a l i t e m s , t h e f a c t o r i n v a r i -

a n t e f o r m e n a n d w o m e n , a n d s i m i l a r p a t t e r n s o b -

s e r v e d b e t w e e n d r u g u s e a n d h e a l t h f o r b o t h s e xe s i n

p r e v i o u s c r o s s - s e c t i o n a l r e s e a r c h [ 3 9 ] , m a l e s a n d f e -m a l e s w e r e c o m b i n e d f o r t h e l a t e n t - v a r ia b l e a n a l y s es

t o f o l l o w .

• M e a s u r e m e n t m o d e l

A c o n f i r m a t o r y f a c t o r a n a l y s i s m o d e l w a s t e s t e d t o

d e t e r m i n e w h e t h e r t h e o b s e r v e d v a r i a b l e s r e f l e c t e d

t h e t e n l a t e n t c o n s t r u c t s a s h y p o t h e s i z e d . I n t h i s

m o d e l a l l f a c t o r v a r i a n c e s w e r e f i x e d a t u n i t y f o r

i d e n t i f i c a t i o n p u r p o s e s , a l l h y p o t h e s i z e d f a c t o r l o a d -

i n g s w e r e f r e e d , a l l c o n s t r u c t s w e r e a l l o w e d t o c o r -

r e l a t e f r e el y , a n d r e s i d u a l s o f r e p e a t e d v a r i a b l e s w e r e

c o r r e l a t e d a c r o s s t i m e . T h i s i n i t i a l m e a s u r e m e n t

m o d e l d i d n o t a d e q u a t e l y r e f l e ct th e d a t a( Z : = 1 03 2.3 4, d f = 3 7 8 , P < 0 . 0 0 1 ) . H o w e v e r . th e

n o r m e d f i t i n d e x ( N F I [ 58 ]) w a s o v e r 0 . 8 7 , i n d i c a t i n g

t h a t m i n o r m o d e l m o d i f i c a t i o n s s h o u l d l e a d t o a

b e t t e r f it t in g m o d e l . F a c t o r i n t e r c o r r e l a t i o n s f o r t h is

i n i t i a l m o d e l a r e g i v e n i n T a b l e 3 .

B a s e d o n a n e x a m i n a t i o n o f th e r e s id u a l m a t r i x

a n d m o d i f i c a t i o n i n d i c e s [ 5 9 ] , s e v e r a l f a c t o r l o a d i n g s

a n d a c o u p l e o f d o z e n s m a l l r e s id u a l c o r r e l a t i o n s

w e r e a d d e d t o t h e m o d e l . T h i s m o d e l a d e q u a t e l y

f it t h e d a t a ( ; ( : = 3 1 3 . 3 6 , d f = 3 1 7 , P = 0 . 5 5 ,

N F I = 0 .9 6 ). F a c t o r i n t e r c o r r e l a t i o n s f o r t h i s f in a l

Table 3. Factor intercorrelations for the initial (upper triangle) and final (lower triangle) confirmatory factor models

Factor I II III IV V VI VII VIII IX X XI

1 C ig ar et te se LA 1.00 0.46** 0.55** 0.38** 0. 12 t 0.14,* 0.I0" -0. 11 t 0.18,* 0.18~ 0.0 8?I I A lc o h o luse LA 0.46** 1.00 0.74** 0.53** 0 . 1 2 t 0.1 4.* 0.15.* -0 .0 4 0.03 0.1 0t 0.00III Cannab isuse LA 0.54** 0.72** 1.00 0.74 0. 10 " 0. 16 ~. 0 .1 4 ~ -0 .02 0.06 0. 07 -0.01IV H ar d dr ug use LA 0.41", 0.52** 0.67** 1.00.+ 0.20** 0.21.* 0.36** -0 .01 0 .1 1 + 0 .1 2t 0.02V Su bjec tive oor 0.1 If 0 . 1 5 t 0 . 1 4 t 0.25 * 1.00 0.67~, 0.61.* -0.73~ 0.34** 0.53** 0.10*

health LAVI Physical symptom index 0. I 1+ 0. 13 ,~ 0 .1 5 ~ 0.18** 0.69, 1.00 0.35** 0.32,+ 0 .3 0 ~ 0,44** 0.09**VII H ea lth service 0.09 0.14t 0 . 1 3 t 0.30,* 0.65** 0.38** 1.00 -0 .2 7 ,+ 0.18.* 0.35** 0.12t

utilization LAVIII Physical hardiness YA -0 .10 t -0.0 2 -0 .03 -0.0 2 -0.44** -0.34** -0.28** 1.00 -0.60** -0.61.* -0. 12 tIX Subj ective health 0.21.* 0.03 0.06 0.12+ 0.3 3,+ 0.29** 0.18.* -0.53,+ 1.00 0.72.+ 0.30,*

problems YAX Ph ysi ca l ym ptom atolog y 0.18.* 0.09 = 0 . 0 9 " 0 .1 4 + 0.61.* 0.64** 0.34** -0.66** 0.77** 1.00 0.27,+

Y AX I H e a l thserv'ice 0.09+ 0.02 0.04 0.085" 0.t3 .* 0.11.* 0.20,+ -0 .1 3. * 0.32, 0.27** 1.00

utilization Y A

*P < 0.05; tP :g 0.01; **P ~ 0.001.LA = late adolescence. YA = young adulthood.

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76 MICHAEL D. NEWCOMB and P. M. BENTLER

Late adolescence

Cigarettequantity

Cigarettefrequency

( ~ Seer frequency

( ~ W i n e frequency

~ j Liquo r frequency

M a r i j u a n a

freduency

Hashishfrequency

Sedativefrequency

Shmulant

frequency

P s y c h e d e l i c

frequency

T im e s f e l t

really ill

Illnesssensitive

I P h y s i c a l

symptom index

Times seenphysician

for emergency

Times seenp h y s i c i a n

for illness

0.62 " ~ * use

Nights inhospital

Young adulthoC<i

Not resistantto fl lness

Health worse ~ @t h a n earlier

Very hardy ~ @

Illnesssensitive

HaPPy withhealth

{eaH'h problems~)ast 4 years

Have trouble

with health

Respiratorysymptoms

~syct~osomaric ~ _ @symptoms

Seizuresymptoms

Times feltreally ill

Times seen ~ )physioian

for illness

Nights inhospital

4ospitalizohonspast 4 years

physicianfor emergent!

Fig. 1. Fin al confirm atory fac tor analysis mo del. Loadings are standardized (*P <0 .05; **P _<0.01;***P < 0.00l) and residual variables are variances. Not depicte d in the figure are two-headed arrows(correlations--see Tab le 3) joining e ach possible pair of latent factors (circles) and the physical s~xnptom

index.

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Adolescen t d rug use and

m e a s u r e m e n t m o d e l a r e a ls o p r e s e n t e d in T a b l e 3,

a n d w e r e q u i t e s i m i l a r t o t h e p r e l i m i n a r y e s t i m a t e s .

C o r r e s p o n d i n g f a c t o r c o r r el a t i o n s w e r e c o r r e la t e d

q u i t e h i g h l y ( r b e t w e e n i n i t i a l a n d f i n a l

m o d e l = 0 . 9 9 ) , i n d i ca t i n g t h a t t h e m o d e l m o d i f i -

c a t i o n s d i d n o t d i s t o r t t h e g e n e r a l m o d e l a n d p a t t e r n

o f l a t e n t c o n s t r u c t a s s o c i a t i o n s . S t a n d a r d i z e d f a c t o r

l o a d i n g s a n d r e s i d u a l v a r i a n c e s f o r t h i s f i n a l c o n -f i r m a t o r y f a c t o r a n a l y s i s m o d e l a r e p r e s e n t e d i n F i g .

1 . T h e l a r g e c i r c l e s r e p r e s e n t t h e l a t e n t f a c t o r s , t h e

r e c t a n g le s a r e t h e o b s e r v e d o r m a n i f e s t v a r i a b l e s , a n d

t h e s m a l l c i r c l e s p o i n t i n g a t t h e r e c t a n g l e s a r e r e -

s i d u a ls o r m e a s u r e m e n t e r r o r s o f t h e m a n i f e s t v a ri -

a b l es . T h e p h y s i c a l s y m p t o m i n d e x i s a m e a s u r e d

v a r i a b l e t h a t i s n o t c o n s i d e r e d a n i n d i c a t o r o f a n y

f a c t o r , a n d a s s u c h i t i s i n a r e c t a n g l e , b u t h a s n o

a r r o w s p o i n t i n g a t i t ( i t i s n o t g e n e r a t e d o r ' c a u s e d '

b y a l a t e n c y c o n s t r u c t ) .

T h e a d d e d f a c t o r l o a d i n g s i n d i c a t e t h a t t h e t e n -

d e n c y t o u s e h a r d d r u g s w a s a s s o c i a t e d w i t h m o r e

p h y s i c i a n v i s i t s f o r e m e r g e n c i e s , a n d t h a t t h e i n c l i n a -t i o n t o w a r d s u b j e c t i v e p o o r h e a l t h w a s a s s o c i a t e d

w i t h i n c r e a s e d q u a n t i t y o f c i g a r e tt e u s e a n d i n c r e a s e d

f r e q u e n c y o f se d a t i v e u s e. S e v e r a l o t h e r c o m p l e x

f a c t o r l o a d i n g s ( v a r i a b l e s t h a t l o a d o n m o r e t h a n o n e

f a c t or o r c o n s t ru c t ) w e r e n e e d e d a m o n g t h e y o u n g

a d u l t c o n s t r u c t s . T h e s e i n d i c a t e t h a t c e r t a i n m a n i f e s t

v a r i a b l e s te n d e d t o b e i n d i c a t o r s o f m o r e t h a n o n e

l a t e n t t e n d e n c y o r c o n s t r u c t , a l t h o u g h t h e r e is n o

o v e r l a p i n v a r i a n c e , s in c e e a c h c o n s t r u c t a c c o u n t s f o r

a u n i q u e a n d e x c l u s i v e p o r t i o n .

S t r u c t u r a l m o d e l

A s e r i e s o f s t r u c t u r a l m o d e l s w e r e t e s t e d u s i n g

t h e f in a l m e a s u r e m e n t m o d e l t h a t a l l o w e d : ( 1) al la d o l e s c e n t c o n s t r u c t s t o b e a r b i t r a r i l y c o r r e l a t e d ; ( 2 )

e a c h y o u n g a d u l t c o n s t r u c t t o b e p r e d i c t e d f r o m a l l

young adu l t hea l th s ta tus 77

a d o l e s c e n t c o n s t r u c t s ; a n d ( 3 ) a l l f a c t o r r e s i d u a l s i n

y o u n g a d u l t h o o d t o b e a r b i t r a r i l y c o r r e l a t e d . D u e t o

t h e l a r g e c o r r e l a t i o n s a m o n g t h e f o u r su b s t a n c e u s e

c o n s t r u c t s , v a r i o u s s u p p r e s s o r e f fe c ts e m e r g e d f r o m

t h e a c r o s s - t i m e a n a l y s e s . T o m i n i m i z e t h e s e s u p -

p r e s s o r e f f e c t s , t h e f o u r s u b s t a n c e u s e f a c t o r s w e r e

u s e d a s i n d i c a t o r s o f a s e c o n d - o r d e r f a c t o r o f g e n e r al

d r u g u s e. T h i s g e n e r a l f a c t o r w a s t h e n u s e d t o p r e d i c tl a t e r h e a l t h c o n s t r u c t s .

T h i s i n i t i a l s t r u c t u r a l o r r e g r e s s i o n m o d e l i s a

c o n s e r v a t i v e b e g i n n i n g p o i n t , a n d d o e s n o t b i a s t h e

r e s u l t s f o r o r a g a i n s t f i n d i n g e f f e c t s o r d r u g u s e o n

h e a l t h . N o r e g r e s s i o n e f f e c t s a r e i m p o s e d w i t h i n

o c c a s i o n , a n d t h u s a l l i n d e p e n d e n t c o n s t r u c t s o r

v a r i a b l e s ( t h o s e f r o m l a t e a d o l e s c e n c e ) a r e p e r m i t t e d

t o c o r r e l a t e f r e e l y . T h u s , a n y s i g n i f i c a n t p a t h f o u n d

a c r o s s t i m e w i l l b e a u n i q u e e f f e c t t h a t c o n t r o l s f o r a l l

o t h e r i n d e p e n d e n t v a r i a b l e s .A f i n a l m o d e l w a s d e r i v e d b y d e l e t i n g u n n e c e s s a r y

( n o n - s i g n i f i c a n t ) p a t h s a n d a d d i n g e s s e n t i a l p a t h s

b e t w e e n l a t e n t a n d / o r m a n i f e s t v a r i a b l e s . T h i s f i n a l

m o d e l f i t th e d a t a e x c e p t i o n a l l y w e l l ( Z - ' = 3 3 6. 92 ,

d f = 3 4 5 , P = 0 . 6 1 , N F I = 0 . 96 ) . A s s o c i a t i o n s a m o n g

a l l l a t e n t c o n s t r u c t s a n d t h e p h y s i c a l s y m p t o m i n d e x

a r e p r e s e n t e d i n F i g . 2 , w h e r e a s e f f e c t s b e t w e e n

m a n i f e s t v a r i a b l e s o r b e t w e e n l a t e n t a n d m a n i f e s t

v a r i a b l e s a re s u m m a r i z e d i n T a b l e 4 .

A s a p p a r e n t i n F ig . 2 , g e n e r a l d r u g u s e h a d a

s i g n i fi c a n t a n d d i r e c t i m p a c t o n d e c r e a s i n g s u b j e ct i v e

p h y s i c a l h a r d i n e s s , b u t d i d n o t d i r e c t l y a f fe c t a n y

o t h e r y o u n g a d u l t c o n s t r u c t . A d o l e s c e n t s u b j e c t i v e

p o o r h e a l t h s i g n i f i c a n t ly p r e d i c t e d y o u n g a d u l t l a c k

o f s u b j e c ti v e p h y s i ca l h a r d i n e s s , p h y s i c a l s y m p t o m -

a t o l o g y , a n d s u b j e c t i v e h e a l t h p r o b l e m s , b u t d i d n o t

d i r e c t l y i n f l u e n c e l a t e r h e a l t h s e r v i c e u t i l i z a t i o n . T h ea d o l e s c e n t p h y s i c a l s y m p t o m i n d e x s i g n i f i c a n t l y

i n f l u e n c e d y o u n g a d u l t p h y s i c a l s y m p t o m a t o l o g y .

Table 4. Direct cau sal effects not depicted in figure

Late adolescencePredictor variable

Observed variable Latent variable Observed variable

Young adulthoodConsequent variable

Latent variable

Standm"dizedparameterestimate*

Cigarette useC i g a r e t t e quan tity (R)')"Cigarette quantity (R)

Cigarette use (R)Cigarette useCigarette useCigarette useCigarette useCannabis use

Psychedelic freque ncy (R)Psychedelic frequen cy (R)

Hard dru g useSubjective poor health

Illness sensitive (R)Illness sensitiveIllness sensitive (R)

Health serviceutilization

Nights in hospitalTimes fe lt really sick

N i g h t s i n hospitalTimes fe lt really sick

Health serviceutilization

Health worse than earlierVery hardyNights in hospitalNights in hospital

Psychosomatic symptom sRespiratory symptomsHave trouble with healthHealth problem s past 4 yearsHealth problems past 4 yearsTimes seen physician for illnessRespiratory symptomsHave trouble with healthHospitalization past 4 yearsRespiratory symptomsNot resistant to illnessVery hardyTimes seen physician for

emergencyHave trouble with healthHave trouble with healthHappy with health

Health problems past 4 years

0.06+*- 0 . 0 7 ~

0.G~0.09~0.13o . ~ :o.!6"0.16¶0.12~

-0 . o 5 ;-0 . o ' ~

oA2,~0.11~0 . 1 2 ¶

0.27-0 .19 •

0.16¶0.II,~

-0.)_~

0.16O.iO~

*Significance evel determined by a critical ratio of the unstandardized parameter estimate divided by its standard error.")'(R) deno tes variab le residual.~P <0.05; §P < 0.01; ¶P ~ 0.001.

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78 MlCH~L D . NEWCOMB and P. M. BENTLER

Adolescent cigarette use and health ser,dce utiliza tion

directly predicted young adult health service utiliza-

tion. Adolescent cann abis use significantly decreased

subjective physical hardiness in young adulthood.

General d rug use was significantly correlated with

both subjective poor health, the physical symptom

index, and health service utiliz ation during ado-

lescence, Due to these correlations and the stabilitypaths of the health status and medical care con-structs, general drug use had an indirect impact onlater decreased health and increased use of health

services. The residual of hard drug use was also

correlated with adolescent poor health and health

service utilization. This indicates that specific hard

drug use, not related to general drug use, indirectly

influenced young adult decreased health quality and

use of medical services. Finally , all factor residualswere significantly correlated at young adul thood.

As summarized in Table 4, general cigarette use

and amount of cigarette smoking were significantly

predictive of increased psychosomatic symptoms,respiratory symptoms, health problems past 4 years,

and nights spent in the hospital, and decreasedhardiness and healthiness. Hard drug use was also

significantly associated with increased trouble with

health. Cannabis use was significantly related to

Late adolescence

• 0 . 1 4 ~

Young adulthood

C igare t teuse

A I c o h o l

us e

C a n n a b i s

use

General

drug use

p h y s i c a l

h a r d i n e s s

health

problems

- 0 . 4 8 ~ *

H ard d ru (

use 0 . 6 8 ~ * ~

O.2 0 " * *

Sub jec t i v e

poor

h e a l t h

0 .24

P h y s i c a l

s y m p t o m -

a to logy

0.70 ~

Physicalsymptom

i n d e x

Health

serv ice

ut i l i za t i on

0.38'~'~

• Health

service

u t i l i z a t i o n

0 . 2 4 ' " "

Fig. 2. Final structural model depicting significant relationships between all latent factors and the physicalsymptom index (*P < 0.05; **P 5; 0.01; ***P _< 0.001). Parameter estimates are standardized and residual

variables are variances.

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Adolescent drug use and young adult health status 79

i n c r e a s e d h e a l t h p r o b l e m s d u r i n g t h e p a s t 4 y e a r s .

T w o s m a l l e f fe c t s o f p s y c h e d e l i c f re q u e n c y o n l a t e r

p o o r h e a l t h v a r i a b l e s ( r e s p i r a t o r y s y m p t o m s a n d

t i m e s s e e n p h y s i c i a n f o r i l l n e s s ) w e r e o p p o s i t e i n s i g n

t o t h e s i m p l e c o r re l a t i o n s , in d i c a t i n g t h a t t h e y a r e

s u p p r e s s o r e f f e c t s a n d n o t i n t e r p r e t a b l e . O t h e r d i r e c t

e f f e c t s o f e a r l y h e a l t h v a r i a b l e s o n l a t e r h e a l t h v a r i -

a b l e s w e r e a l s o n o t e d . F o r i n s t a n c e , t h e s y m p t o mi n d e x i n a d o l e s c e n c e w a s d i r e c t l y a n d s i g n i f i c a n t l yp r e d i c t i v e o f t h e p h y s i c a l s y m p t o m a t o l o g y f a c t o r i n

y o u n g a d u l t h o o d .

Alternate model

A l t h o u g h t h e m o d e l p r e s e n t e d a b o v e i n d i c a t e s

s e v e r a l s m a l l , b u t s i g n i f i c a n t , e f fe c ts o f t e e n a g e s u b -s t a n c e u s e o n c h a n g e s i n h e a l t h o v e r t i m e , i t i s

p o s s i b l e t h a t t h e s e a r e s i m p l y ' f i n e - t u n i n g s ' o f a l a r g e

m o d e l a n d n o t r e a l l y i m p o r t a n t o r n e c e ss a r y . I n o r d e r

t o t e s t t h i s n o t i o n , w e f i x e d a l l a c r o s s - t i m e r e -l a t i o n s h i p s b e t w e e n a l l d r u g v a r i a b l e s a n d l a t e r h e a l th

v a r i a b l e s t o z e ro . T h i s o p e r a t i o n a l i z e s t h e h y p o t h e s i st h a t d r u g u s e i s u n r e l a t e d t o h e a l t h s t a t u s o r h e a l t hc a r e o v e r t i m e . T h e r e s u l t a n t m o d e l d i d n o t a d e -

q u a t e l y r e f l e c t t h e d a t a ( Z - ' = 4 4 8 . 0 9 , d f = 3 6 2 ,

P = 0 . 0 0 1 , N F I = 0 . 9 4 ) , a n d , m o r e i m p o r t a n t l y , w a sa s i g n i f i c a n t ly p o o r e r f i t t h a n t h e f i n a l m o d e l

p r e s e n t e d a b o v e ( d if fe r e nc e Z 2 = 1 1 1 . 1 7 , d f = 1 7 ,

P < 0 .001) . This ind ica te s tha t the e f f ec t s o f d r ug use

o n h e a l t h v a r i a b l e s o v e r t i m e a r e i m p o r t a n t f e a tu r e so f th e f i n a l m o d e l , a n d t h a t t h e n u l l m o d e l t h a t d r u g

u s e a n d h e a l t h a r e u n r e l a t e d a c r o s s t i m e c a n b er e j e c t e d w i t h g r e a t c e r t a i n t y .

DISCUSSION

T h i s s t u d y a t t e m p t e d t o d e t e r m i n e t h e h e a l t hc o n s e q u e n c e s l a t e r i n l i f e o f u s i n g d r u g s d u r i n g

a d o l e s c e n c e . W h i l e s o m e r e s e a r c h h a d d e m o n s t r a t e d

t h a t p r o b l e m d r i n k i n g i n a d o l e s c e n c e is p r e d ic t i v e o f

y o u n g a d u l t p r o b l e m d r i n k i n g , im p l y i n g a d e c re m e n ti n p h y s i c a l h e a l th d u e t o e x c e ss i v e a l c o h o l c o n s u m p -

t i o n [ 5 ] , n o s o l i d r e s e a r c h h a s s p e c i f i ca l l y s h o w n t h a t

t e e n a g e d r u g u s e ca u s e s d e t e r i o r a t e d h e a l t h o v e r t i m e .

T h e r e c e n t s t u d y b y B r u n s w i c k a n d M e s s e r i [ 3 9 ]

p u r p o r t s t o t e s t t h i s r e l a t i o n s h i p , b u t d o e s s o w i t hl a r g el y c o n c u r r e n t a n d r e t ro s p e c t i v e m e a s u r e s. T h u s ,

t h e c u r r e n t s t u d y i s o n e o f t h e f i r s t t o u s e t r u l y

l o n g i t u d i n a l d a t a t o t e s t f o r t h e e f f e c t s o f a d o l e s c e n t

d r u g u s e o n c h a n g e s i n h e a l t h s t a t u s t h r o u g h y o u n ga d u l t h o o d .

S e v e r a l c a u t i o n s a r e n e c e s s a r y w h e n e v a l u a t i n g t h er e s u l t s o f t h i s s t u d y . F i r s t , t h e r e s u l t s a r e b a s e d o n

s e l f - r e p o r t m e a s u r e s a n d m a y n o t r e f le c t t r u e d r u g u s e

c o n s u m p t i o n n o r p h y s i c a l h e a l t h p r o b l e m s . H o w e v e r ,

s t u d ie s h a v e s h o w n t h a t s e l f - r e p o r t m e a s u r e s o f d r u gu s e c o n v e r g e w i t h o t h e r m e t h o d s o f a s s e s s m e n t [6 0 ],

a n d t h a t s e l f - r e p o r t a s s e s s m e n t s o f h e a l t h s t a t u s a r eg o o d i n d i c a t o r s o f o b j e c t iv e h e a l t h e v a l u a t i o n s [ 6 1].S i m i l a rl y , s e lf - r e p o r t m e a s u r e s o f e m o t i o n a l d i s tr e s s

h a v e b e e n t h e b e s t i n d i c a t o r s o f m o r t a l i t y [ 62 ] .F i n a l l y , n o m o r e t h a n 3 6 % o f t h e v a r i a n c e o f y o u n g

a d u l t h e a l t h s t a t u s w a s a c c o u n t e d f o r b y t h e a d o -l e s c e n t c o n s t r u c t s , i n d i c a t i n g t h a t o t h e r v a r i a b l e s a r en e c e s s a r y t o c a p t u r e a l a r g e r p o r t i o n o f t h e y o u n g

a d u l t h e a l t h s t a tu s o u t c o m e s ( su c h a s s o c i a l s u p p o r t ,h e a l t h p r a c t i c e s , o r s t r e s s f u l e v e n t s ) . G i v e n t h e s e

l i m i t a t i o n s , h o w e v e r , t h i s s t u d y p r o v i d e s a n e s s e n t i a l

p r e l i m i n a r y , a t t e m p t t o u n d e r s t a n d t h e h e a l t h c o n -

s e q u e n c e s o f t e e n a g e d r u g u s e .

T h e m o s t o b v i o u s c o n c l u s i o n f r o m t h e s e ri e s o f

a n a l y s e s p r e s e n t e d i s t h a t t e e n a g e d r u g u s e h a s a

r e l a t i v e l y s m a l l , b u t s t a t i s t i c a l l y s i g n i f ic a n t , i m p a c t o n

c h a n g e s i n p h y s i c a l h e a l t h a n d h e a l t h s e r v i c e u t i l i z a -

t i o n 4 y e a r s l a t e r a s y o u n g a d u l t s . C o m p a r i n g t h e f i to f t h e n u l l h y p o t h e s i s m o d e l ( w h i c h c o n s t r a i n e d a tz e r o a l l e ff e ct s o f e a r l y d r u g u s e o n l a t e r h e a l t h s t a t u s )

w i t h t h e f i t o f t h e f i n a l m o d e l i n d i c a t e s t h a t a b o u t 2 %o f t h e v a r i a n c e i n t h e m o d e l i s a c c o u n t e d f o r b y t h e

i m p a c t o f e a r l y d r u g u s e o n l a t e r h e a l t h s t a t u s . A sn o t e d a b o v e , t h i s i s a h i g h l y s i g n i f i c a n t i n c r e m e n t , b u ti n t e rm s o f m a g n i t u d e i s n o t o v e r w h e l m i n g .

T h e s t a b i l i t y ef fe c t s b e t w e e n e a r l y a n d l a t e r su b j e c -

t i v e h e a l t h s t a t u s , o b j e c t i v e s y m p t o m r e p o r t i n g , a n d

u t i l i z a t i o n o f m e d i c a l s e r v i c e s w e r e a l l s i z a b l ea n d s i g n i f ic a n t . T h u s , e v e n t h o u g h t h e a d o l e s c e n t a n d

y o u n g a d u l t i n d i c a t o r s o f h e a l t h s t a t u s w e r e n o t

c o n s i s t e n t l y i d e n t i c a l ( w i t h t h e y o u n g a d u l t a s s e s s -m e n t s s u b s t a n t i a l l y e x p a n d e d ) , t h e l a t e n t c o n s t ru c t su n d e r l y i n g o r g e n e r a t i n g t h e s e m e a s u r e s w e r e q u i t e

s i m i l a r , a s r e f l e c te d i n t h e i r s t a b i l i t y o v e r t i m e . T h i s

i s a d i s t i n c t a d v a n t a g e o f l a t e n t - v a r i a b le m e t h o d s( w i t h c a r e f u l l y s e l e c t e d i n d i c a t o r s ) o v e r s t a n d a r d ,

m e a s u r e d - v a r i a b l e m e t h o d s . S u b s t a n t iv e l y . as e x -

p e c t e d , t h e s t a b i l i t y e f fe c t s i n d i c a t e t h a t t h e a d o -l e s c e n t p h y s i c a l s y m p t o m i n d e x s i g n i f i c a n t ly p r e -

d i c t e d y o u n g a d u l t p h y s i c a l s y m p t o m a t o l o g y , t h a t

a d o l e s c e n t s u b j e c t i v e p o o r h e a l t h s i g n i f i c a n t l y i n -f l u e n c e d y o u n g a d u l t s u b j e c t i v e p h y s i c a l h a r d i n e s s ,

s u b j e c t i v e h e a l t h p r o b l e m s , a n d p h y s i c a l s y m p t o m -a t o l o g y , a n d t h a t a d o l e s c e n t h e a l t h s e rv i c e u t i l i z a t i o n

s i g n i f i c a n t l y i n f l u e n c e d y o u n g a d u l t h e a l t h s e r v i c eu t i l i z a t i o n . A s a r e s u l t o f t h e s e r e l i a b l e s t a b i l i t y

e f f e c t s , a n d t h e f a c t t h a t t h e e a r l y d r u g u s e m e a s u r e s

w e r e a l l o w e d t o c o r r e l a t e w i t h e a r l y h e a l t h s t a t u sm e a s u r e s , a n y s i g n i f i c a n t a c r o s s - t i m e i n f l u e n c e o f

e a r l y d r u g u s e o n l a t e r h e a l t h s t a t u s c a n b e i n t e r -

p r e t e d a s a p o s s i b l e c a u s a l i n f lu e n c e o n c h a n g e s i n t h eh e a l t h s t a t u s a s s e s s m e n t s .

T h e p r e s e n t r e s u l t s i n d i c a t e t h a t g e n e r a l a d o l e s c e n t

s u b s t a n c e u s e , r e p r e s e n t i n g a v a r i e t y o f d r u g s , w a ss i g n i f i c a n t l y r e l a t e d t o d e c r e a s e d s u b j e c t i v e p h y s i c a l

h a r d i n e s s 4 y e a r s l a t e r , a f t e r c o n t r o l l i n g f o r p r i o r

l e v e ls o f p o o r h e a l t h a n d h e a l t h s e r v i c e u t i l i z a t i o n .

N o o t h e r d i r e c t e ff e ct s w e r e f o u n d f o r g e n e r a l d r u gu s e o v e r t i m e . H o w e v e r , g e n e r a l d r u g u s e a n d t h e

s p e c if i c u s e o f h a r d d r u g s w e r e s i g n i f i c a n t l y c o r r e l a t e dw i t h s u b j e c t i v e p o o r h e a l t h a n d h e a l t h s e r v ic e u t il i z a -

t i o n d u r i n g a d o l e s c e n c e (a s w e r e g e n e r a l d r u g u s e a n dt h e p h y s i c a l s y m p t o m i n d e x ) , w h i c h i n t u r n , w e r e

s i g n i f i c a n t l y r e l a t e d t o y o u n g a d u l t h e a l t h s t a t u s .T h u s , i n d i r e c t i n fl u e n c e s o f a d o l e s c e n t d r u g u s e b o t h

g e n e r a ll y , a n d f o r h a r d d r u g s i n p a r t i c u l a r, m a y o c c u ro n l a t e r p h y s i c a l d e t e r i o r a t i o n t h r o u g h t h e m e d i a t i n gi n fl u e n ce o f a d o l e s c e n t s u b j e c t iv e p o o r h e a l t h a n d t h ep h y s i c a l s y m p t o m i n d e x . H o w e v e r , t h i s m o d e l w a s

n o t t e s te d d i r e c t l y s i nc e t h is w o u l d r e q u i re r e c e s s i o np a t h s w i t h i n t i m e , w h i c h w o u l d b i a s t h e r e s u l t s .

S p e c i f ic c i g a r e t t e u s e ( n o t r e l a t e d t o g e n e r a l d r u g u s e )a l s o l e d t o d e c r e a s e d s u b j e c t i v e p h y s i c a l h a r d i n e s s i ny o u n g a d u l t h o o d .

I t i s p o s s i b l e t h a t a d e c r e a s e i n s u b j e c t i v e p h y s i c a lh a r d i n e s s p r e c e d e s t h e d e v e l o p m e n t o f s p e c i f i c i l l -

_ . ,

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80 MICHAEL D. NEw coM 8 and P. M. BENTLER

n e ss e s a n d s o m a t i c s y m p t o m a t o l o g y . T h i s su g g e s ts

t h a t t h e d i r e c t i n f l u e n c e o f d r u g u s e, c i g a r e t t e s m o k -

i n g, a n d c a n n a b i s u s e o n l o w e r i n g p h y s i c a l h a r d i n es s ,

m a y i n t i m e l e a d t o s p ec i f i c a n d i d e n t i f i a b l e h e a l t h

p r o b l e m s . I t is r a t h e r a l a r m i n g t h a t e v e n o v e r t h is

r e l a ti v e l y s h o r t p e r i o d o f 4 y e ar s t h a t n o t i c e a b l e

e f f e c ts o n p e r c e i v e d p h y s i c a l r e s i s t a n c e t o i l l n es s w e r e

e v i d e n t i n t h i s g e n e r a l s a m p l e , w i t h o n l y a s m a l lp e r c e n t a g e o f h e a v y d r u g u s er s .

I n g e n e r a l , t h e r e s u l t s s u g g e s t t h a t g e n e r a l t e e n a g e

d r u g u s e d e c r e a se d s u b j e c t i v e o r p e r c e i v e d h e a l t h

q u a l i ti e s , b u t d i d n o t i n c r e a s e r e p o r t i n g o f o b j e c t iv e ,

p h y s i c a l s y m p t o m s . O n l y c i g a r e t t e u s e i n c r e a s e d

p h y s i c a l s y m p t o m r e p o r t i n g o v e r t h e 4 - y e a r p e r i o d .

N o p o s i t i v e e f f ec t s o f t e e n a g e d r u g u s e o n l a t e r h e a l t h

s t a t u s w e r e f o u n d ( e x c e p t f o r t w o s m a l l s u p p r e s s o r

e f f ec t s ). T h e r e w e r e n o d i r e c t e f f e c t s o f a l c o h o l u s e o n

a n y h e a l t h c o n d i t i o n .

S p e c i f i c u s e o f c i g a r e t t e s s e e m e d t o h a v e c a u s e d

g r e a t e r s p e c i f i c h e a l t h p r o b l e m s ( i .e . r e s p i r a t o r y

s y m p t o m s , s u b j e c t i v e h e a l t h p r o b l e m s , d e c r e a s e i n

s u b j e c ti v e p h y s ic a l h a r d i n e ss ) a n d u s e o f m o r e m e d i -

c a l s e r v i c e s o v e r t h e 4 - y e a r p e r i o d , t h a n a l l o t h e r

d r u g s . T h u s i n t e r m s o f p h y s i ca l h e a l t h c o n s e q u e n c e s ,

i n q u a n t i t i e s u s e d b y t h e s e a d o l e s c e n t s , c i g a r e t t e s m a y

b e m o r e d e s t r u c t i v e o v e r a s h o r t p e r i o d o f t i m e t h a n

o t h e r l i c it o r i l l i c it d r u g s i n c l u d i n g c a n n a b i s a n d

h a r d e r d r u g s . A l t h o u g h t h e d e s t ru c t i v e p o t e n t i a l f o r

s m o k i n g c i g a r e t te s h a s b e c o m e a w e l l - k n o w n f a c t

[ 29 , 6 3] , i t h a s r a r e l y b e e n n o t e d f o r s u c h a y o u n g

s a m p l e , h a v i n g r e l a t iv e l y s h o r t s m o k i n g c a r e e rs , a n do v e r s u c h a r e l a t iv e l y b r i e f p e r i o d o f t i m e . A s s u c h ,

t h e s e r e s u l t s p r o v i d e i m p o r t a n t n e w i n f o r m a t i o n

r e g a r d i n g t h e c o n s e q u e n c e s o f te e n a g e c i g a r e t t e

s m o k i n g .S p e c if i c e f f ec t s o f c a n n a b i s u s e w e r e f o u n d o n

c h a n g e s i n s u b j e c t i v e o r p e r c e i v e d h e a l t h c o n d i t i o n s

o v e r t h e 4 y e a r s . E a r l y c a n n a b i s u s e l e d t o d e c r e a s e d

s u b j e c ti v e p h y s i c a l h a r d in e s s a n d i n c r e a s e d h e a l t h

p r o b l e m s i n t h e p a s t 4 y e a r s . T h e r e w e r e n o

s i g n i f i c a n t e f f e c t s o f c a n n a b i s u s e o n c h a n g e s i n

p h y s i c a l s y m p t o m r e p o r t i n g o r u t i l i z a t i o n o f m e d i c a l

s e rv ic e s .

H a r d d r u g u s e l e d t o a s u b je c t i v e a p p r a i s a l o f

h a v i n g t r o u b l e w i t h h e a l t h i n y o u n g a d u l t h o o d . I n

a d d i t i o n , a n u n e x p e c t e d f a c t o r l o a d i n g w a s n e e d e d

f o r th e h a r d d r u g u s e c o n s t r u c t d u r i n g t h e a d o l e s c e n t

p e r i o d . T h i s l o a d i n g i n d i c a t e d t h a t t h e t e n d e n c y t o

u s e h a r d d r u g s a l s o g e n e r a t e d i n c r e a s e d v i s it s t o

p h y s i c i a n s b e c a u s e o f e m e r g e n c i e s . T h u s , h a r d d r u g

u s e w a s r e l a t e d t o p r e c i p i t o u s u s e o f h e a l t h s e r v i c e s

d u e t o e m e r g e n c y s i t u a t i o n s a n d a p e r c e p t i o n o v e r -

t i m e o f i n c r e a s e d h e a l t h p r o b l e m s . T h e s e i n d i c a t e

p o t e n t i a l l y d a n g e r o u s c o n s e q u e n c e s o f h a r d d r u g u s e

t h a t c a n n o t b e a n t i c i p a t e d a n d t e n d t o b e o f a n

i m m e d i a t e a n d p e r h a p s c r is i s n a t u r e .

T h e s e f i n d i n g s i n d i c a t e c l e a r l y t h a t t h e r e a r e s o m e

p h y s i c a l h e a l t h c o n s e q u e n c e s a n d s o c i a l c o s t s ( in -

c r e a s e d u s e o f m e d i c a l s e r v ic e s ) t o y o u t h f u l d r u g u s e

[ 23 , 2 4] , a n d i n p a r t i c u l a r c i g a r e t t e s m o k i n g [ 29 ]. A l l

t y p e s o f d r u g u s e , a n d i n p a r t i c u l a r c a n n a b i s a n d

c i g a r e t t e u s e , w e r e a s s o c i a t e d w i t h d e c r e a s e d p e r -c e i v e d p h y s i c a l h a rd i n e s s , w h i c h w i t h c o n t i n u e d d r u g

i n v o l v e m e n t m a y l e a d to m o r e p r o n o u n c e d p h y si c a l

c o m p r o m i s i n g e f fe c ts . I t i s p o s s i b l e t h a t d r u g u s e o v e r

a g r e a t e r l e n g t h o f t i m e m a y h a v e a d i r e c t e f f e ct o n

m a j o r h e a l t h p r o b l e m a n d s y m p t o m s , w h i ch w e r e n o t

a p p a r e n t i n th i s s t u d y w i t h t h e e x c e p t i o n o f c i g a r e t t e

u s e .

A c k n o w l e d g e m e n t s - - T h i s research was partia lly supportedby gran t DA01070 from the Na t iona l Ins t i tu te on DrugAbuse . Com pute r a s s is tance o f Sandy Yu and prod uc t ion

assis tance o f Ju l ie Speckart a re warm ly acknowledged .

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