eastern mediterranean health journal

Upload: ana-ferreira

Post on 02-Jun-2018

218 views

Category:

Documents


0 download

TRANSCRIPT

  • 8/9/2019 Eastern Mediterranean Health Journal

    1/9

    Eastern Mediterranean Health Journal | Back to Health Journal page | Health Journal

    back issues| Home

    Drug addiction: a general review of new concepts and future challenges

    N.A. Qureshi, Y.S. Al-Ghamdy and T.A. Al-Habeeb

    Print this article Your e-mail:

    Recipient e-mail:

    E-mail this article

    Volume 6, Issue 4, 2000, Page 72!7

    SUMMARY Relevant papers published in peer reviewed journals in the past 2 decades wereidentiied and screened to abstract pertinent inormation! Substance dependence"addiction# involvin$both a common brain reward mechanism and lon$er-lastin$ molecular and cellular chan$es# is apreventable chronic# relapsin$ brain disease and as such a public health problem! Ph%sical andps%cholo$ical dependence# characteri&ed b% withdrawal s%ndrome# are now $iven less wei$htcompared with compulsive behaviour and uncontrolled use o dru$s in the comprehension oaddiction! 'he challen$in$ components o dru$ addictions# includin$ counteradaptation# sensiti&ation#abstinence# cravin$ and relapse need urther neurobiolo$ical and non-neurobiolo$ical e(ploration andunderstandin$# which ma% be possible throu$h the use o advanced ima$in$ and $enetic techni)uesand animal models o dru$ addiction to$ether with relevant human studies!

    Introduction

    *ver the past 2 decades# dramatic advances in behavioural neuroscience have $reatl% enhanced our

    understandin$ o substance abuse and dependence! Recentl%# the ollowin$ three-sta$econceptuali&ation o dru$-ta+in$ behaviour appl%in$ to all ps%choactive dru$s has been proposed , 1!

    . /ru$ use: reers to the ta+in$ o dru$s# in the narrow sense# to distin$uish it rom a more intensiiedpattern o abuse!

    . /ru$ abuse: reers to an% harmul use# re$ardless o whether the behaviour constitutes a disorder in/SM-01 o the American Ps%chiatric Association ,2!

    . /ependence: reers to substance dependence as deined b% /SM-01 ,2 or addiction as deined b%0/ 34 ,3!

    /ia$nostic criteria o substance dependence 56o( 37have also been urther reined ,2! Althou$h it isa challen$in$ tas+ to deine dru$ addiction# 8eather best deined it as repeated ailures to rerain romdru$ use despite prior resolutions to do so ,4! 8e urther characteri&ed the behaviour and e(perienceo the dru$ addict b% three central eatures: conlict# ambivalence and decision-ma+in$! 6ased onthese eatures# he proposed a three-level conceptual ramewor+ or e(plainin$ addiction# whichconsists o the level o neuroadaptation# the level o desire or dru$s and the level o a+rasia# orailure o resolve! 8owever# 6i$elow and associates view dru$ abuse as a learned operant behaviourthat is reinorced b% the positive eects produced b% dru$s o abuse ,5! Accordin$l%# the%characteri&ed dru$ abuse as involvin$ attraction rather than compulsion ,5! *ther researchers havee(pressed similar views# but with compulsion as an inte$ral part o the phenomenon o addiction ,6!'ian% and arter characteri&ed compulsive dru$-ta+in$ as an automati&ed behaviour that tends tobe stimulus-bound# stereot%ped# eortless# diicult to control and re$ulated lar$el% outside oawareness ,! 9oob and associates deined substance dependence as a compulsive behaviour and

    presented evidence throu$h separate animal models that e(plained most o the dia$nostic criteria orsubstance dependence ,!! Some researchers consider the concept o compulsive dru$ use no

    http://www.emro.who.int/emhj.htmhttp://www.emro.who.int/Publications/EMHJ/index.asphttp://www.emro.who.int/Publications/EMHJ/index.asphttp://www.emro.who.int/index.asphttp://window.print%28%29/http://box1%28%29/http://box1%28%29/http://www.emro.who.int/emhj.htmhttp://www.emro.who.int/Publications/EMHJ/index.asphttp://www.emro.who.int/Publications/EMHJ/index.asphttp://www.emro.who.int/index.asphttp://window.print%28%29/http://box1%28%29/
  • 8/9/2019 Eastern Mediterranean Health Journal

    2/9

    lon$er useul in the e(planation o addiction ,4! i+ewise# the ph%sical and ps%cholo$ical dependencealso ma% not matter# nor the ph%siolo$ical component ,2,4! /espite considerable dru$ abuseresearch# there is still no international consensus on the deinition o substance abuse anddependence"addiction!

    At the biolo$ical level# mesocorticolimbic dopamine is reco$ni&ed as the underl%in$ neurochemicalsubstrate o compulsive dru$ use ,"! Moreover# researchers have identiied and cloned the receptorsand natural li$ands o most substances o abuse! ;or e(ample# researchers have identiied andcloned a tetrah%drocannabinol 5'87 receptor in the rat brain ,1#! Ph%lo$eneticall%# it is e(pectedthat the human brain ma% have similar '8 receptors that are aected b% cannabis use! Additionall%#biochemical# cellular and molecular cascades within the cell that ollow receptor activation b% dru$s oabuse have been partl% revealed! Researchers have urther revealed subtle dama$e to thedevelopin$ brain as a result o etal cocaine e(posure , 11 and rontal lobe injur% as evidenced b%decreased

  • 8/9/2019 Eastern Mediterranean Health Journal

    3/9

    not# these patients have co-morbid a(is-0 disorders ,1",2# and a(is-00 personalit% disorders ,21#which should be addressed appropriatel% while considerin$ the overall mana$ement o such patients!

    Drug dependence and the social perspective

    Substance dependence cannot be understood without describin$ the social settin$s in which itdevelops! 0t adversel% aects the ph%sical# ps%cholo$ical and social health o both the individual andthe $eneral public! 0t is a disease o sociall% disadvanta$ed people# and stressul conditions arepotential ris+ actors in the development o substance dependence and abuse! 'his has been ampl%illustrated b% studies related to post-traumatic stress disorder and dru$ dependence identiied amon$1ietnam >ar veterans# and survivors o earth)ua+es# car accidents# rape# +idnappin$s# hijac+in$sand shootin$s! 0n addition to causin$ other health and social problems# substance dependence is animportant vehicle in the spread o major inectious diseases such as ac)uired immunodeicienc%s%ndrome 5A0/S7# hepatitis and tuberculosis! 'here is a lar$e bod% o literature that stron$l% attests tothe relationship between these diseases and substance abuse and dependence# in particular cocaineabuse! /ru$ addiction is also a major cause o homicides!

    Addiction is a major public health problem? hence# its treatment should include basic public healthapproaches# such as health promotion and education throu$h national and international campai$ns#primar% prevention# treatment# rehabilitation# relapse prevention and social services! 0t is evident thatsociet% and the relevant authorities are movin$ in ri$ht direction in order to achieve these $oals! 'hele$ali&ation o substances o abuse# an e(tremel% challen$in$ tas+ in some cultures# has bothadvanta$es and limitations! 0t has been reported that commercial access is associated with $rowth inthe dru$-usin$ population ,22!

    $iological considerations

    /ru$ dependence is viewed as a chronic brain disease because it is reported to produce chan$es inthe d%namic unctionin$ o the brain! 0t is now well +nown that the dru$ e(posure episode activatesspeciic structures# neurotransmitters and other related chemicals within the neurons and associated

    receptors ,23! 0t also leaves behind a memor% trace that persists lon$ ater the dru$ has disappearedrom the bod%! Such dru$ e(posures are usuall% paired with environmental and social cues thatthrou$h conditionin$ ac)uire the abilit% to activate the same or complementar% brain circuits# even inthe absence o dru$ e(posure! Such lon$-term persistent eects have been studied directl% rombehavioural ,24# structural and molecular perspectives ,25# usin$ a variet% o advanced ima$in$techni)ues in human studies and animal models o dru$ addiction!

    ;urthermore# it has been revealed that the chan$es in brain metabolic activit% and hormones# $enetice(pression# receptor densit%# and responsiveness to environmental cues dierentiate the brains oaddicted people rom those o non-addicted individuals! 0n two recent studies# $enot%pe associatedwith midbrain serotonin transporter bindin$ sites and mR

  • 8/9/2019 Eastern Mediterranean Health Journal

    4/9

  • 8/9/2019 Eastern Mediterranean Health Journal

    5/9

    i!e! lon$-term potentiation and spatial memor% ,23,41!

    Ps%chological and ph%siological dependence

    Recentl%# it has been emphasi&ed that ps%cholo$ical and ph%sical dependence on addictive dru$s isnot as important as the compulsive see+in$ o dru$s and their uncontrolled use ,1,2,16! 'his isbecause dru$s o abuse do not produce these eatures with e)ual intensit%# althou$h the% all aectthe same mesolimbic reward s%stem# which e(tends rom the ventral te$mentum to the nucleusaccumbens with projections to the limbic s%stem and the orbitorontal corte(! 'he predicted commonmechanisms o reinorcement b% various dru$s o abuse are also supported b% several studies,4,42,43! ;urthermore# these substances aect the brain at all levels! 8owever# /SM-01 criteria 56o(37 still include the ph%siolo$ical component# as deined b% tolerance and withdrawal# in the dia$nosiso dru$ dependence!

    Schuc+it et al!# in a stud% o alcohol-dependent patients with and without withdrawal or tolerance#reported that patients with withdrawal s%mptoms showed more severe alcohol dependence ,3#! 'hiswas indicated b%: hi$her number o drin+s consumed in 2D hours? more bin$es reported? more

    alcohol-related lie problems? more relevant /SM-000R criteria endorsed? more ph%siolo$icalcomplications? and more alcohol-related emotional"ps%chiatric s%mptoms such as depression andan(iet%! 'he% also ound that the most severe clinical course o alcoholism was predicted b% thepresence o withdrawal# which deines the ph%siolo$ical component o dependence! 'hese importantindicators o dru$ dependence severit% were independent o $ender and antisocial personalit%disorder! *ther researchers have substantiated these indin$s ,44! 8owever# the data are insuicientto draw an% conclusion between ph%siolo$ical components and dru$ abuse severit% ,31,45# inparticular cocaine abuse! ;urthermore# 3!3G o the subjects denied meetin$ the criteria orph%siolo$ical dependence and DB!CG $ave no histor% o withdrawal s%mptoms ,3#!

  • 8/9/2019 Eastern Mediterranean Health Journal

    6/9

    neurotransmitter s%stems# such as the dopamine /2 receptor ,5# a-aminobut%ric acid ,5!#noradrenaline ,5" and $lutamate!

    &onclusions and future research implications

    Substance dependence is a major public health problem! 0t adversel% inluences the ph%sical# mentaland social health o the dru$ abusers and the public at lar$e! 'hereore# the principles o thecommunit% health paradi$m should be applied in dealin$ with this modern epidemic! At the sametime# it is a social problem# so the sociolo$% o dru$ abuse should ocus on several important socialdimensions# includin$ stress# povert%# domestic and societal violence and various diseases that arespread b% dru$ abuse and addiction! Most importantl%# appropriate cultural and reli$ious prescriptionsshould be encoura$ed in the control o this disease!

    'he conceptuali&ation o addiction as a chronic# relapsin$ brain disease also has multiple implicationsand oers man% opportunities# such as access to treatment acilities or patients with substance usedisorders! 'here should be continuin$ mass media campai$ns hi$hli$htin$ the most devastatin$conse)uences o dru$ addiction and at the same time disseminatin$ current inormation and

    attemptin$ to chan$e attitudes towards addicted patients! Sel-help $roups and related or$ani&ationsworldwide can be o tremendous help in achievin$ this objective! 'his would help in brid$in$ thee(istin$ inormation $ap between clinicians and the public!

    ;urthermore# neuroscience and social research should continue to e(plore the neural substrates andps%chosocial determinants underl%in$ dierent aspects o dru$ addiction# includin$ tolerance#sensiti&ation# abstinence# cravin$ and relapses! Moreover# $enetic research on dru$ addiction shouldtar$et its phenot%pes and related $enetic mar+ers in order to develop $enetic therapies or thetreatment o patients who ma% be predisposed to addiction! 'he cascade o acute chan$es in theneuronal networ+ ollowin$ dru$ e(posure# i!e! neurobiolo$%# is bein$ researched and urther studiesshould ocus on revealin$ the lon$-term neuronal chan$es lin+ed to dru$ addiction!

    0t is now +nown that relapses in dru$ abuse patients are usual# and thereore relapse prevention

    strate$ies should be e(plored urther! 'he individual and environmental mechanisms underl%in$relapse should be addressed on a continuin$ basis# and appropriate dru$s and ps%chosocialtherapies should be used to prevent relapse! Substance-addicted patients# whether livin$ in prison orin the communit%# are essentiall% suerin$ rom a chronic brain disease in the orm o substanceabuse and dependence! 'he% re)uire acute and lon$-term maintenance treatment and relapseprevention# complemented b% suitable rehabilitation! 'hese are some o the challen$es posed b%dru$ abuse and addiction that should be addressed appropriatel% b% the scientiic communit% incollaboration with societ%!

    "c'nowledgements

    'he authors than+ the sta o the *nline Search /ivision o 9in$ Abdul A&i& it% or Science and

    'echnolo$%# Ri%adh or providin$ the relevant literature!

    References

    3! 0nstitute o Medicine! $a%h&ays '( addi)%i'n! >ashin$ton /#

  • 8/9/2019 Eastern Mediterranean Health Journal

    7/9

    3@@B# 32:-C!

    F! 6i$elow E# 6rooner R9# Silverman 9! ompetin$ motivations: dru$ reinorcement vs non-dru$reinorcement! 'urnal '( 0sy)h'0harma)'l'+y# 3@@B# 32:B-3D!

    H! *I6rien P et al! onditionin$ actors in dru$ abuse: can the% e(plain compulsionJ 'urnal '(0sy)h'0harma)'l'+y# 3@@B# 32:3F-22!

    C! 'ian% S'# arter 6! 0s cravin$ the source o compulsive dru$ use 'urnal '(0sy)h'0harma)'l'+y# 3@@B# 32:2-4!

    B! 9oob ; et al! Substance dependence as a compulsive behavior. 'urnal '( 0sy)h'0harma)'l'+y#3@@B# 32:@-DB!

    @! /i hiara ! A motivational learnin$ h%pothesis o the role o mesolimbic dopamine in compulsivedru$ use! 'urnal '( 0sy)h'0harma)'l'+y# 3@@B# 32:FD-HC!

    34! Matsuda A et al! Structure o a cannabinoid receptor and unctional e(pression o the clonedc/

  • 8/9/2019 Eastern Mediterranean Health Journal

    8/9

    2D! *I6rien P! E(perimental anal%sis o conditionin$ actors in human narcotic addiction!$harma)'l'+i)al reie 3@CF# 2C:F-D!

    2F! indell 9! /ru$ addiction: a model or the molecular basis o neuralplasticit%! Neur'n# 3@@# 33:@@F-344H!

    2H! ittle 9Y et al! ocaine# ethanol# and $enot%pe eects on human midbrain serotonin transporterbindin$ sites and mRic+el$ren 0! 'eachin$ the brain to ta+e dru$s! S)ien)e# 3@@B# 2B4:24DF-H!

    D3! 9entros et al! Abolition o lon$-term stabilit% o new hippocampal place cell maps b%

  • 8/9/2019 Eastern Mediterranean Health Journal

    9/9

    durin$ cannabinoid withdrawal! S)ien)e# 3@@C# 2CH:24F4-D!

    DD! 6uchol& 99 et al! an we subt%pe alcoholismJ A latent class anal%sis o data rom relatives oalcoholics in a multicenter amil% stud% o alcoholism. Al)'h'lism, )lini)al and e0erimen%al resear)h#3@@H# 24:3DH2-C3!

    DF! Rounsaville 6K# 6r%ant 9K! 'olerance and withdrawal in the /SM-333-R dia$nosis o substancedependence: utilit% in a cocaine-usin$ population!Ameri)an 'urnal 'n addi)%i'ns# 3@@2# 3:F4-H4!

    DH! Edwards ! >ithdrawal s%mptoms and alcohol dependence: ruitul m%steries!ri%ish 'urnal '(addi)%i'n# 3@@4# BF:DDC-HC!

    DC! Schuc+it MA! Substance-related disorders! 0n: >idi$er 'A et al!# eds! *S-/ s'ur)eb''7# vol! 3>ashin$ton /# American Ps%chiatric Association# 3@@D: F-3@!

    DB! ottler 6 et al! A$reement between /SM-000 and 000-R substance use disorders. *ru+ and al)'h'lde0enden)e# 3@@3# 2@:3C-2F!

    D@! ottler 6 et al! 'he /SM-01 ield trial or substance use disorders: major results . *ru+ andal)'h'l de0enden)e# 3@@F# B:F@-H@!

    F4! idi$er 'A et al!# eds . *S-/ s'ur)eb''7#vol! 3 >ashin$ton /# American Ps%chiatric Association# 3@@D: -D!

    F3! S+inner 8A! Alcohol dependence: how does it come aboutJ ri%ish 'urnal '( addi)%i'n# 3@BH#B3:2C@-BD!

    F2! 9alant 8#