Behac. Res. Ther. Vol. 28. No. 3. pp. 235-242. 1990 0005-7967/90 $3.00 + 0.00 Printed in Great Britain. All rights reserved Copyright bl 1990 Pergamon Press plc

THE IMPACT OF RECURRENT HEADACHES ON

BEHAVIOR LIFESTYLE AND HEALTH

REN~E LACROIX’* and HOWARD E. BARBAREE’

‘Department of Psychology. McGill University, 1205 Docteur Penfield Avenue, Montreal, Quebec and ‘Department of Psychology, Queen’s University, Kingston, Ontario, Canada

(Received 28 November 1989)

Summary-The goal of this study was to examine whether behavioral avoidance was pervasive in a sample of headache sufferers as has been suggested by Philips (Behavior Research and Therapy, J&273-279. 1987). One hundred and fifty participants provided retrospective evaluations of behavior changes perceived to have resulted from repeated exposure to headache pain. The outcome of these self-assessments underscored marked changes in several domains of behavior and overall lifestyle. This evidence therefore provided support for Philips’ position since the changes appeared persistent, even during pain-free states.

INTRODUCTION

Recently, Philips and her colleagues proposed that behavioral avoidance is an important contributor to chronic headache pain (Philips, 1987; Philips & Hunter, 1981; Philips & Jahanshahi, 1985). Using the Pain Behavior Questionnaire (PBQ) to measure behavior, Philips and Jahanshahi (1985) argued that avoidance behavior is prominent with chronic sufferers and disproportionate to the pain experienced. Moreover, these behavioral reactions are believed to reduce feelings of control over the pain and serve to maintain the headache problem.

On the other hand, Radnitz, Appelbaum, Blanchard, Elliott and Andrasik (1988) have argued that avoidance behavior may simply be the natural outcome of headache intensity. After treating 86 headache sufferers by means of behavioral techniques they reported a substantial reduction on all measures of the PBQ, thereby suggesting that there existed, in fact, a close association between pain and behavior. Once the pain was relieved, the behavior changes ceased to be evident.

One possible explanation for these discrepant findings may be due to the use of the PBQ as an index of behavior change. Initially. the items on this instrument were chosen for their ability to represent behaviors apparent during pain states and Ss who initially were involved in validating this instrument were required to indicate which activities they “performed when suffering a usual headache” (p. 260) (Philips & Hunter, 1981). As a consequence, many of the items retained for inclusion in the PBQ are particularly sensitive to behavioral respones to pain (i.e. avoid noise, lie down, take prescription tablets, grip, rub or stroke area in pain). It may not be unusual to find that this behavior is no longer present during pain-free states (Radnitz et al., 1988).

The aim of the present study was to examine the behavioral changes that are made by headache sufferers as they attempt to cope with the recurrent pain. In this instance, the Comprehensive Pain Questionnaire (Monks & Taenzer, 1985) was used since it allowed for the assessment of a wide range of behaviors, including behavioral changes that may persist during pain-free states. It was hypothesized that chronic headache has a substantial impact on several dimensions of the sufferer’s behavior and overall lifestyle.

METHOD

Subjects

One hundred and fifty (150) participants consented to fill out the Comprehensive Pain Questionnaire (CPQ) that sought retrospective accounts of headache-associated changes. Of those participants, 46 (30.7%) were referred to the study by a neurologist. Three physicians in the Neurology Department of the Montreal General Hospital, Montreal, Quebec, agreed to collaborate

*To whom all correspondence should be addressed.

235

236 REN~E LACROIX and HOWARD E. BARBAREE

and to refer patients to the study. Another 68 (45.3%) participants were recruited through newspaper and television coverage of the study in Montreal. Finally, 36 (24%) of the remaining participants were volunteers from introductory psychology classes attending Queen’s University at Kingston, Ontario.

Recruiting from three different sources ensured that the range of headache sufferers was broad; that is, their symptoms ranged from the severe to milder and less chronic forms of headache. All participants had to meet three criteria for acceptance into the study: (1) at least one headache per month; (2) the pain is not continuous or unrelenting; (3) 18 yr of age or older.

Procedure und materials

Participants were told about the nature of the study by a handout which described both the purpose and the work involved in participating. Specifically, they were informed that they would receive a questionnaire by mail that they were to complete. Moreover, they were given telephone access to the experimenter throughout in case any concerns or questions arose. When all their questions were answered, they were instructed to complete a consent form.

The initial questionnaire provided basic demographic information as well as retrospective self-assessments of the psychological consequences of headache. Some of the information included retrospective accounts of headache; frequency, intensity and duration. In addition, Ss completed the Brief Headache Symptom Questionnaire (Arena, Blanchard, Andrasik & Dudek, 1982) which was used to assist in the classification of headache type, the McGill Pain Questionnaire (Melzack, 1975) which provides a qualitative assessment of pain, and the Psychosomatic Symptom Checklist (Cox, Freunlich & Mayer, 1975) which is useful in assessing the presence and severity of a number of psychosomatic conditions.

Portions of the Comprehensive Pain Questionnaire (CPQ) (Monks & Taenzer. 1985) were also administered. This relatively new instrument was devised in order to tap into the wide range of variables important in the assessment of chronic pain. To date, this instrument has not been evaluated for its psychometric properties. It is however, a useful clinical tool, in that it yields data about (a) organic factors that may be suggested from the pain history; (b) psychosocial problem areas; (c) pain, its modifiers and the consequences of pain. Because of the extensive nature of this questionnaire, a shortened version was adapted for this study. The last two items of this version were obtained from Barnat and Lake (1983) and assess patient perceptions of the degree to which pain interferes with daily living.

RESULTS

Characteristics of the sample

Eighty-one percent (n = 122) of the total sample (n = 150) were women with an average age of 37.0 yr. The remaining 18.7% (n = 28) were men with a mean age of 39.3 yr. The age range of this sample was between 18 and 73 yr with a mean of 37.5. Of this sample, 36% were between 18-30 yr of age. 22% were between 3140 yr, 22% were between 41-50 yr, 12% were between 51-60 yr and 7% were 61 yr and over.

Characteristics qf the sample’s headache pain

Table 1 presents the proportion of Ss endorsing each of the categories for headache frequency, intensity and duration. The average intensity of headaches for this sample (measured on a l-5 point scale) was 3.9. No significant differences were found between men and women.

Table 2 provides the mean scores on the three subscales of the McGill Pain Questionnaire. These scores are compared to the values reported by Melzack (1975) for a group with cancer pain and another with dental pain. Our sample reported sensory descriptions of pain that were slightly lower than those reported by cancer patients but an evaluative component that is substantially less than these patients. The most striking difference, however, is that the affective reaction to the pain was almost twice as high as the one reported by cancer patients. Each of these scores was further broken down by gender. Outcome of F-tests on these three scales indicate women reporting higher scores than men on the affective scale, F(l,148) = 3.9; P < 0.05

The impact of recurrent headaches 237

Table I. of Ss each category measures of freouencv. intensitv duration

Item

Frequency of Headaches Everyday At least 3 days/week At least I day/week At least 2 days/month At least I day/month

Intensity of Headaches Very mild, aware of it only when attending to it Mild, can be ignored at times Severe, difficult to concentrate Extremely intense, incapacitating

Duration of Headaches 1 hr or less 24 hr 7-12 hr 13-18 hr 19-24 More than 24 hr

Percentage

10.1 26.2 16.8 28.2 18.7

0.0 25.5 56.4 18.1

4.0 35.6 20. I 12.8 11.4 16.1

Table 3 presents the scores obtained on the Psychosomatic Symptom Checklist (PSC). These scores are contrasted with those obtained from a group of adults screened to exclude psychophys- iological disorders and a second group of headache sufferers described in Attansio, Andrasik, Blanchard and Arena (1984). With a total PSC score of 22.4, this sample scored substantially higher than a group of adults screened to exclude psycho-physiological disorders (mean = 9.7) and slightly lower than a sample of unscreened college students (mean = 23.7). The PSC scores are further broken down for men and women and are found to show significant differences with women showing higher scores on this index, F(1,146) = 9.91; P < 0.002.

Finally, based on the Brief Headache Questionnaire, it is clear that most Ss fell into the mixed headache (49.7%) and the muscle-contraction headache groups (35.9%). On average, this sample had suffered from headaches for 15.5 yr with a range of l-55 yr. Women had suffered for an average of 15.2 yr and men 16.6 yr, these were not reliably different from each other.

Retrospective perceptions of headache impact

The retrospective evaluation of the impact of headache on the sufferer’s life is based on the answers to questions found in the CPQ. These questions have been divided into three categories: (1) impact on lifestyle; (2) impact on general health; (3) overall appraisal of headache impact.

The first category, impact on lifestyle, comprises questions relating to: (a) work; (b) finances; (c) leisure; and (d) social and family life. The second category, impact on general health, involves questions dealing with: (a) sleep; and (b) health-related habits. Finally, the last category, overall appraisal of headache impact, is based on two multiple choice questions where participants rated the extent to which the headaches have had an effect in their life and overall well-being.

Perceptions of headache’s impact on lifestyle

Impact on work andjnances. Overall, 65% of respondents stated that headaches affected their ability to carry out their occupation (see Table 4). Thirty-two percent reported experiencing decreased satisfaction with their work and 20% found that the headaches interfered with their

Table 2. Means (standard deviations) for scores obtained on the McGill Pain Questionnaire along with the mean scores obtained in a group experiencing cancer pain and another with dental pain. The mean

scores are broken down by gender

Scale Sample mean

Cancer Dental pain pain mean mean

Mean for Mean for women men

McGill Pain Questionnaire Sensory Pain Rating

Affective Pain Rating

Evaluative Pain Rating

15.9 17.3 I I.8 17.7 14.2 (8.7) (9.7) (7.7) 4.0 2.3 I.7 5.0 3.0

(3.9) (4.9) (3.0) 2.6 4.1 2.2 2.8 2.5

(1.4) (1.4) (1.4)

238 E. BARBAREE

Table 3. Means (standard deviations) for scares obtained on the Psychosomatic Symptom Checklist along with the mea” scores reported for a group of adults screened to exclude psychophysiological disorders and a second

er”“” of headache sufferers (Attansio et a/.. 1984). The mea” sc”res are broken down bv gender

Scale

Psychosomatic Symptom Checklist Frequency Index

Severity Index

Total Score

ss Current Healthy Attansio Mean for Mean for Sd”lple adults el al. w0men me”

Il.6 13.7 9.5 (7.0) (7.3) (6.7) 10.8 13.0 8.6 (5.7) (6.5) (4.9) 22.4 9.7 28.0 26.7 18.1

(12.0) (13.1) (10.9)

ability to get along with coworkers. For 17% of the sample, a job change was necessary because of the pain. Finally, 20% believed that their headaches prevented them from taking on a salaried job. Only one participant received disability payments because of headaches. Of the sample, 16% felt that the headaches prevented them from having an adequate income and consequently were in financial need (see Table 5).

Impact on leisure, social and family Aye. Of the 146 respondents, 21% reported having discontinued specific leisure activities because of their headaches (see Table 6). This item appeared particularly relevant for women with 25% endorsement compared to 7% for men.

Twenty-six percent of our sample reported making changes in their social life while 15% reported making changes with friends and 12% with the family. Once again, women reported more frequent disturbances in these areas with 31% reporting overall social changes, 17% with friends and 21% with family. In contrast, 7% of men reported making changes in their social life, 3% with friends and 7% with family.

Perceptions of headache’s impact on general health

Impact on sleep. As indicated in Table 7, 74 out of 146 Ss reported having changed their sleep habits since the onset of their headaches. Each S was asked to indicate what type of sleep problems they experienced and to choose more than one category when appropriate. As a result, 20% reported taking a long time to fall asleep, 25% woke during the night, 15% woke too early in the morning. Finally, 6% reported not feeling refreshed in the morning. Women consistently reported more sleep problems, and, of the 8% who reported taking medication to help them sleep, all of them were women.

Impact on health-related habits. On the question of weight change, 22% of the sample answered in the affirmative, whereas only 8% felt their appetite had increased since the start of the headaches.

Table 4. R~SDO”S~S on the Comprehensive Questionnaire

Women Men

n ReSDO”Se % n % n %

Work

Have the headaches caused any change in your work? 146 Yes 65.1 81 67.5 I4 53.8

no 34.9 39 32.5 12 46.2 Has there been any change in the type of work you do because of the headaches?

146 Yes 17.1 20 16.8 5 18.5 no 82.9 99 83.2 22 81.5

Has there been any changes with the satisfaction you obtain frown your work?

139 less 32.6 40 34.8 5 20.8 “mre 3.6 5 4.3 0 0 same 63.8 70 60.9 19 79.2

Has there been any changes in how you get along with co-workers?

139 w0rse 20.9 25 21.9 4 16.0 better 2.9 4 3.5 0 0 same 76.3 85 74.6 ?I 84.0

If you do not obtain a salary for your work, would you get a salaried job if it weren’t for the headaches?

87 Yes 20.7 I3 1x.3 5 31.3 no 79.3 58 81.7 II 68.8

The impact of recurrent headaches

Table 5. Responses on the Comprehensive Pain Questionnaire

239

Women Men

n Response % n % n %

Finances

Are you receiving an income for your headache disability? 146 Yes 1.4 I 0 0

no 98.6 I21 0 0 Are you in financial need?

138 yes 17.4 I9 16.8 5 20.0 82.6 94 83.2 20 80.0

Do you be&: that the headaches play a role in your financial need? 75 yes 16.0 8 13.1 4 28.6

no 84.0 53 86.9 IO 71.4

Table 6. Responses on the Comprehensive Pain Questionnaire

Women Men

n Response % n % n %

Leisure

Are there any hobbies, sports. recreational and social activities that you no longer do because of the headaches?

146 yes 21.9 30 25.2 2 1.4 no 78.1 89 74.8 25 92.6

Are there new activities that you have begun since the headaches began?

143 yes 22.4 26 22.4 6 22.2 no 77.6 90 77.6 21 77.8

Social and family life

Have you changed how much you do socially because of the headaches?

146 yes 26.8 37 31.1 2 7.4

Have your ryationships 73.2 82 68.9 25 92.6

with your friends changed because of the headaches?

147 yes 15.0 21 17.5 I 3.7 no 85.0 99 82.5 26 96.3

Has your family life changed because of the headaches? 132 Yes 12.9 25 21.6 2 7.7

no 87.1 91 78.4 24 92.3

Table 7. Responses on the Comprehensive Pain Questionnaire

Women Men

n Response % n % n %

Sleep

Have your sleep habits changed since you started the headaches? 146 yes 50.7 64 53.8 IO 37.0

no 49.3 55 46.2 17 63.0 Sleep has improved

146 Yes 0.7 I 0.8 0 0 no 99.3 II8 99.2 27 100.0

I take longe: to fall asleep 146 yes 20.6 27 22.7 3 11.1

no 77.4 92 71.3 24 88.9 I awaken more often at night

146 yes 25.3 30 25.2 4 14.8 no 74.7 89 74.8 23 85.2

I awaken too early in the mornmg 146 Yes IS.1 20 16.8 2 7.4

no 84.9 99 83.2 25 92.6 I use medication to sleep

146 yes 8.9 I3 10.9 9 0 no 91.1 106 89.1 27 100.0

I don’t feel refreshed in the morning as I used to 145 Yes 6.9 40 33.6 6 22.2

no 93.1 79 66.4 21 17.8 Other sleep problems

145 yes 6.9 8 6.6 2 7.7 no 93. I III 91.0 24 92.3

240 REN&E LACROIX and HOWARD E. BARBAREE

Table 8. Resoonses on the Comarehensive Pain Ouestionnaire

WOtlE” Me”

n Response % n % n %

Health-related habits

Has Your weight changed significantly since You started the headaches?

146 Yes 22.8 27 22.7 6 23.1 “0 77.2 92 77.3 20 16.9

Has your appetite changed since your started the headaches? 141 1.3s 10.0 14 12.3 I 3.1

“IOR 8.7 8 7.0 5 18.5 same 75.3 92 80.7 21 77.8

Do you smoke more or less when you have headaches? 79 less 87.3 53 85.5 I6 94.1

more 3.8 3 4.8 0 0 same 8.9 6 9.7 I 5.9

Do you drink alcohol to relieve the headache pain? 146 Yes 4.8 6 5.0 I 3.8

“0 95.2 II4 95.0 25 96.2 Do you drink alcohol to relax?

146 Yes 17.6 32 26.9 8 30.8 “0 72.4 87 73.1 18 69.2

Do you drink alcohol to sleep? I44 Yes 2.1 3 2.5 0 0

“0 97.9 115 91.5 26 100.0 Have you had problems because of alcohol?

I41 yes 4.3 5 4.3 I 3.8 “0 95.7 II0 95.7 2s 96.2

Ten percent (10%) experienced a decrease in appetite but the majority reported no appetite changes (see Table 8).

With regard to cigarette smoking, only 3% reported smoking more during the time that they had headaches, with 87% smoking less. Four percent reported using alcohol to relieve headache pain. Another 17% of our sample reported using alcohol to relax and 2% to help them sleep. A small portion of the sample reported serious problems because of their alcohol consumption.

Overall appraisal of headache’s impact

As indicated in Table 9, 27% of Ss felt their headaches to be their worst problem, and 6% felt it was not as serious as their other problems. Overall, 54% reported headache to be a very serious problem.

When asked whether their life was affected by the headaches, 3% reported that because they had not lived at all, 11% reported that their life could have been richer than it had been with headaches and 23% felt life would have been somewhat richer and more full without the headaches.

DISCUSSION

The aim of this study was to examine the changes made in order to accommodate recurrent headache and which may be manifest during pain-free states. The sample’s appraisal of the impact of pain indicated that many aspects of life were affected. Thirty-eight percent (38%) reported that their life would have been richer without headache. Moreover, 54% reported that headaches were the most serious problem they faced.

These percentages are substantially lower than those reported by Barnat and Lake (1983). They found 53.8% who thought their life would be richer without headache and 70.1% who perceived the headaches to be a very serious problem as compared to their other problems. These

Table 9. Overall appraisal of headache impact

My headache is (compared to other problems) Worse More Equally Less Least by far serious serious serious serious

144 27.8 26.4 18.1 20.8 6.9

Without headache, my life could have been, NO Not much Somewhat Much

richer richer richer Richer richer I44 22.2 38.9 23.6 II.8 3.5

The impact of recurrent headaches 241

discrepancies may well reflect the fact that their sample was made up of patients attending a specialized headache clinic. In contrast, this sample consisted of a variety of headache sufferers, and only 30% were referred by neurologists. It is interesting to note, however, that despite the constitution of the sample, a large number still appraised the headache as having a pervasive impact on their lives.

From the retrospective self-evaluation of the impact of headache on lifestyle it can be seen that 65% of the respondents indicated that the headaches affected their ability to carry out their occupation and 17% had to change jobs because of the headaches. A smaller percentage (21%) felt that specific leisure activities had to be discontinued because of the pain. Interpersonal changes were also reported by 26% of the sample, with 15% making changes with friends and 12% with family.

These results are comparable to the work reported by Pelz and Merskey (1982). In this study, 83 outpatients with diverse pain problems reported on some of the changes caused by pain. The interesting aspect of this sample was that participants were chosen only if the pain was due to a documented physical lesion. Their results indicated that 26% of the sample reduced their leisure and hobby activities and 28% reduced their social activities. Apparently, long-term adjustments to pain are comparable to those reported in the present sample where no evidence of a physical lesion existed.

With respect to health, a rather large portion of the sample (50%) reported long term changes in their sleep patterns and attributed these changes to the pain. Although previous work has considered the relationship between pain and sleep (Parkes, 1985) such large changes were unexpected. Virtually all aspects of sleep were reportedly affected. The questions asked related mostly to disorders of initiating and maintaining sleep, other studies are needed to document whether other types of sleep disturbances may also be prevalent. This kind of work could be helpful in understanding headaches that begin during sleep or upon awakening (Dexter, 1979). The data on other health-related habits suggest that these are relatively unimportant for this sample.

Two additional observations relating to gender differences are particularly relevant since it has been found that 75% of headache sufferers are women (Graham, 1985). The first, is the finding that a much larger proportion of women compared to men report long-term changes in their leisure activities and in their interpersonal life as a consequence of headache. Such reductions may imply reduction of pleasurable activities and more time spent meeting the demands of day-to-day life. Moreover, some psychologists have linked the reduction of pleasurable activities with depression (Lewinsohn, Sullivan and Grosscup, 1982). Although no evidence with regard to this relationship can be derived from the present study, it may be a worthwhile question for future investigations.

Similarly, a reduction in one’s social life may be of concern because it may also imply reduced social support. Again, social support was not measured directly, but may merit attention in future work, because social support may serve as a buffer against poor physical health (Cohen & Wills,

1985). The final point about gender differences relates to the rather large percentage of women who

report sleep disturbances (53 women vs 37% men). Women consistently reported more sleep disturbances for every item of the questionnaire. Although both sexes reported sleep disturbances, only women were taking prescription medication for their sleep problems. The basis for the difference is not known. It is possible that women are more likely to request sleep medication or it may be that doctors are more likely to prescribe to women. Previous work has shown that Canadian women are by far prescribed more hypnotic sedatives than men (Cooperstock,

1976). To conclude, it appears that headache sufferers perceive pervasive long-term changes associated

with recurrent headaches. By means of retrospective assessments, participants indicated that marked changes were apparent in various domains of their lives, even when they were pain-free. Moreover, the changes appear to cover fundamental transactions with their environment including work and relationships with co-workers, family and friends. This evidence therefore supports Philips’ work since evidence was found for persistent behavioral avoidance during pain-free states. It is not known, however, whether these changes are significantly different from the patterns of avoidance seen in patients with pain arising from organic lesions.

242 FCEN~E LACROIX and HOWARD E. BARBAREE

Acknowledgements-Support for this work was provided, in part, by a studentship to the first author from the Medical Research Council of Canada. We would like to thank Dr R. Melzack of McGill University, for his comments on an earlier version of this paper.

REFERENCES

Arena. J. G.. Blanchard. E. B., Andrasik, F. & Dudek, B. (1982). The headache symptom questionnaire: Discriminant classificatory ability and headache syndromes suggested by factor analysis. Journal of Eehaoioral As.Pessment. 4. 5549.

Attansio. V., Andrasik, F., Blanchard, E. B. & Arena, J. G. (1984). Psychometric properties of the SUNYA revision of the Psychosomatic Symptom Checklist. Journal of Behaoioral Mediiine, 7. 247:25f.

Barnat. M. R. & Lake, A. E. (1983). Patient attitudes about headache. Headache. 23. 229-237 Cohen. S. & Wills, T. A. (1985). Stress, social support, and the buffering hypothesis. Psvchologicul Reporr. 98, 310-357. Cooperstock, R. (1976). Psychotropic drug use among women. Canadian Medical Association Journal 115. 760-763. Cox, D. J., Freundlich. A. & Meyer, R. G. (1975). Differential effectiveness of electromyograph feedback, verbal relaxation

instruction, and medication placebo with tension headaches. Journal of‘Consulting and Clinical Psychology, 43. 892--899. Dexter, J. D. (1979). The relationship between stage III and IV and rem sleep and arousals with migraine. Headache. 19,

364-369. Graham, J. R. (1985). Headache. In Aronoff. G. M. (Ed.). Evaluafion and treatment of chronic pain. Baltimore: Urban &

Schwarzeberg. Lewinsohn, P. M.. Sullivan, J. M. & Grosscup, S. J. (1982). Behavioral therapy: Clinical applications. In Rush, A. J. (Ed.),

Short-term ps~~chotherapies for depression. New York: Guilford. Melzack. R. (1975). The McGill Pain questionnaire: Major properties and scoring methods. Pain, I, 2777299. Monks. R. and Taenzer. P. (1985). A comprehensive pain questionnaire. In Melzack, R. (Ed.). Pain nreusurement and

ussessmeni. Raven Press, New York. Parkes. J. D. (1985). Sleep and irs disorders. Toronto: Saunders, Pelz, M. & Merskey. H. (1982). A description of the psychological effects of chronic painful lesions. Pain, 14. 293-301. Philips. H. C. (1983). Assessment of chronic headache behavior. In Melzack, R. (Ed.), Pain measurement and assessment.

pp. 155 165. Raven Press, New York. Philips, H. C. (1987). Avoidance behavior and its role in sustaining chronic pain, Behatliour Research and Therapy. 25,

273-279. Philips. H. C. & Hunter, M. (1981). Pain behavior in headache sufferers. Behaciour Analysis and Mod#cation, 4. 257.-266. Philips. H. C. & Jahanshahi, M. (1985). The effects of persistent pain: The chronic headache sufferer. Puin, 21. 163-175. Radnitz, C. L.. Appelbaum. K. A., Blanchard, E. B., Elliot, L. & Andrasik. F. (1988). The effect of self-regulatory treatment

on pain behavior in chronic headache. Behaciour Research and Therapy. 26, 253-260.