DSM-III Disorders in a Large Sample of Adolescents

DSM~III Disorders in a Large Sample of Adolescents ROB Mc GEE, PH.D ., MICHAEL FEEHAN, DIPCLPS, SHEILA WILLIAMS, B.Sc ., FIONA PARTRIDGE, DIPCLPS, PHIL A. SILVA, PH.D. , AND JANE KELLY , A.B.

Abstract. The prevalence of DSM-III disorders was studied in 943 adolescents aged 15 years from a general population . Prevalence rates of disorder of 25.9% for girls and 18.2% for boys were found. The most prevalent disorders were overanxious disorder, nonaggressive conduct disorder , and simple phobia . Marked differences were noted among the disorders in terms of associated social competence, with multiple disorders and primaril y "externalizing" disorders being related to poorer competence. A model of parental confirmation of disorder was developed suggesting that confirmation was more likely where the mother was depressed , the family low in social support, and the adolescent less socially competent. J . Am . Acad . Child Adolesc. Psychiatry, 1990, 29, 4:611619. Key Words: DSM-lll disorder, adolescents . There are few published epidemiological studies of the prevalence of behavioral and emotional disorders in adolescence. What studies there are suggest that significant numbers of adolescents have mental health problems. Krupinski et al. (1967) reported a prevalence of psychiatric diagnosis among 14- to 2l -year-olds in Heyfield , Victoria (Australia) of 19% for boys and 22% for girls. Leslie (1974), in a study of 13- and l4-year-olds in Blackburn (U.K.), estimated that some 21% of the boys and 14% of the girls had a moderate to severe psychiatric disorder. In the followup study on the original Isle of Wight sample, Rutter et al. (1976) reported a prevalence rate of 8% of the 14- to 15year-olds ; the corrected prevalence estimate, taking account of those not selected on the screening tests, was 21%. More recently, Offord et al. (1987) examined the 6 month prevalence rates for disorder in their 4- to l6-year-old sample of Ontario (Canada) children. For the age range 12 to 16 years , 19% of the boys and 22% of the girls were estimated to have psychiatric disorder. While there are marked differences among these studies in terms of geographical location, year the survey was conducted, and general meth-

odology, the results are remarkably convergent: about one in five adolescents had some kind of mental health disorder. The 20 year period between the Krupinski et al. (1967) and Offord et al. (1987) surveys has been a time of marked change in terms of diagnostic systems. This has been particularly so in the case of disorders of childhood and adolescence, with the introduction of DSM-III and more recently DSM-III-R. As far as we are aware, only two major epidemiological surveys have specifically examined the prevalences of DSM-III disorders in large samples of adolescents from the general population. Cohen et al. (1987) have reported the estimated prevalences of disorders using both DSM-III and revised III-R criteria. Using the latter criteria, the most frequent disorder in their sample of 13to l8-year-olds was oppositional disorder (about 8% of boys and girls); the least frequent was separation anxiety (about I % of boys and girls). Sex differences in disorder were most apparent in the case of conduct disorder with about 3 times as many boys as girls having this diagnosis, and overanxious disorder with about 5 times as many girls as boys. Bird et al. (1988) examined DSM-III disorders in a large sample of Puerto Rican children aged 4 to 16 years and reported an overall prevalence of disorders with associated functional impairment of about 16%. However, while there appear to have been age differences in the prevalences of different disorders, the results for the adolescent age group are not reported in detail. Overall , there is surprisingly little information on the prevalence and correlates of disorders in adolescents , using currently accepted diagnostic criteria. This is at a time when DSM as a diagnostic system is undergoing a series of rapid changes (Werry, 1988; Zimmerman, 1988). The Dunedin Multidisciplinary Health and Development Study (DMHDS) is a longitudinal investigation of the health, development , and behavior of a large sample of New Zealand children. One of the research concerns in this study has been the assessment of mental health in childhood and adolescence. When the sample was aged 11, the prevalence of DSM-III disorders was first examined using interviews with the children , themselves, and parent and teacher questionnaires detailing problem behaviors. Anderson et al. (1987) reported an overall prevalence of DSM-III disorders of about 18%, with some 12% of the sample having a " pervasive" disorder, identified by more than one source.

Accepted March 20 , 1990 . From the Dunedin Multidisciplinary Health and Development Research Unit, Department ofPaediatrics and Child Health (Drs. McGee and Silva and Mr. Feehan), the Department of Psychology (Ms . Partridge) and the Department of Preventive and Social Medicine (Mrs . Williams), Medical School, University of Otago, Dunedin, New Zealand; Ms. Kelly was a Fulbright scholar at the Dunedin Unit and is now involved in additional study at Harvard University. A version of this paper was presented at the fir st annual meeting of the Society f or Research in Child and Adolescent Psychopathology, Miami, Florida , February 1- 3, 1989. The DMHDRU is supported by the Medical Research Council of New Zealand and involves several departments of the University of Otago. Much of the data has been collected by voluntary workers f rom the local community . The authors are indebted to the many people whose valuable contributions continue to make this ongoing study possible. Collection of the mental health data was partially supported by U.s.P B .S. Grants 1-23-MH42723Ol and l-ROI-MH43746 fr om the Antisocial and Violent Behaviour Branch of the US National Institutes of Mental Health. Address correspondence to : Dr. McGee, Dunedin Multidisciplinary Health and Development Research Unit, Department of Paediatrics and Child Health, Medical School, University of Otago, Box 913, Dunedin, New Zealand . 0890-8567/90/2904-0611$02.00/0© 1990by the American Academy of Child and Adolescent Psychiatry.

611

MCGEE ET AL.

The sample has been reassessed at age 13 (Frost et al., 1989), and most recently at age 15. This paper reports on the general findings for the mental health assessment at age 15, describing the general methodology and reporting the prevalences of various DSM-III disorders. The authors also examine the association between mental health disorders and two classes of variables, those measuring social competence and those measuring family adversity. A starting point for an examination of social competence is Garmezy's (1971) description of the "hallmarks of competence" in childhood as "good peer relations, academic achievement, commitment to education and to purposive life goals, early and successful work histories" (p. 114). There are clear associations in the research literature between poor competence in childhood and adolescence and both concurrent levels of problem behaviors (Blechman et al., 1985) and future adult mental health (Felsman and Vaillant, 1987). In this study, the aim was to examine social competence associated with different DSM-III disorders. Previous research from the Dunedin study has documented the strong association between family disadvantage and DSMIII disorders in preadolescent children (Williams et al., 1990). In the present paper, this earlier work is extended by examining the association between family disadvantage and disorder in adolescence. Of particular interest is the nature of the association between family adversity and parent reports of disorder.

Method Sample

The adolescents were enrolled in the DMHDS, a longitudinal investigation of their health, development, and behavior. They belonged to a cohort born at Queen Mary Hospital, Dunedin, between April 1, 1972 and March 31, 1973. They were first assessed at age 3 years when there were 1,139 eligible children living in the province of Otago in which Dunedin is situated. Of these 1,139, 1,037 were enrolled in the study; the remaining children were either traced too late for inclusion or their parents refused participation. The sample has been reassessed every 2 years thereafter, on a variety of medical, developmental, and behavioral measures. The history and characteristics of the sample are fully described by Silva (1990). By age 15, there were eight known deaths. Of the remaining 1,029 adolescents, 852 were assessed at the Dunedin Unit and 117 were interviewed elsewhere in New Zealand, or in other countries (primarily Australia). Information was also collected on an additional seven adolescents who could not be assessed owing to serious developmental retardation. Of those not assessed, 33 refused participation, 11 were not seen for other reasons (for example, being out of the country), and nine could not be traced. The high rate of reassessment was achieved at least in part by (a) offering return air or bus fares to those adolescents living away from Dunedin; (b) offering a shorter home assessment if the adolescent was unwilling or unable to come to the Dunedin unit; and (c) interviewing those living out of New Zealand where possible. 612

The Dunedin sample is socioeconomically advantaged to a certain degree when compared with the remainder of New Zealand on an index of socioeconomic status or SES (Elley and Irving, 1972). Furthermore, the sample is underrepresented in Maori and other Polynesian children when compared with the rest of New Zealand (New Zealand Department of Statistics, 1983). Overall, the sample would be comparable with those from other English-speaking Western cultures. Measures Mental health interview. At age 11, the sample members were interviewed using version XIII-III of the Diagnostic Interview Schedule for Children (DISC-C) (Costello et al., 1982). This is a structured diagnostic interview developed under the auspices of the National Institute of Mental Health. The interview content is based upon criteria for DSM-III disorders of childhood and adolescence. Each question was scored as O-"no, " 1-"sometimes," and 2-"yes," for the preceding 12 months. At ages 13 and 15, the authors were unable to use the full DISC-C because of time constraints on the assessment schedule. In part, this was due to a desire to broaden the mental health assessment to include measures such as family, peer and school attachment, life stress, and general background circumstances. In addition, the majority of sample members did not have disorder and were essentially "symptom-free." Under these circumstances, it was believed that repeated questioning regarding symptoms was inappropriate. It was decided, therefore, to abbreviate the DISC-C, while still allowing an assessment of each DSMIII criterion for disorder. The authors examined coefficient alpha, a measure of reliability based upon internal scale consistency (Nunnally, 1967), and item-total correlations for each set of questions assessing the symptoms for a particular disorder at 11. In many instances, the same DSM-III criterion symptom was assessed by more than one DISC-C question. For each criterion symptom, that DISC-C item with the highest itemtotal correlation was chosen. That is, in the shortened DISCC each symptom was assessed by a single question with original qualifying questions retained where appropriate. Based upon experience with the DISC-C at ages 11 and 13, a series of additional "probe" items was developed to clarify answers where the interviewer was in some doubt as to the severity or pervasiveness of symptoms. Three additional changes were made. First, eight questions assessing obsessive-compulsive disorder were eliminated because of the rarity of the disorder. No cases were identified at age 11, and prevalence studies suggest that probably about 0.3% of the adolescents would have this disorder (Rapoport, 1986). Similarly, questions relating to psychotic disorder and gender identity disorder were not included. To a considerable extent, the research aim of this study has been to focus on more commonly occurring conditions. Second, a "gating" procedure was used in the case of depressive disorders so that initial criteria for depressed mood/anhedonia as well as time criteria for duration of symptoms were to be fulfilled before asking the remaining J.Am.Acad. Child Adolesc. Psychiatry, 29:4, July 1990

DSM-III DISORDERS IN ADOLESCENTS

depression questions. An additional modification was introduced here by assessing major depressive episodes over the last few weeks and past episodes/dysthymia over the last year in two clearly delineated sets of questions. Third, conduct disorder was assessed with a 30-item self-report delinquency scale developed by Moffitt and Silva (1988) for the study of juvenile delinquency and offending. This scale contained full criteria for the assessment of both aggressive and nonaggressive conduct disorder. The abbreviated DISC-C interview provided for the assessment of the following disorders : (1) anxiety disorders including overanxious, separation anxiety, social phobia, and simple phobia disorders; (2) depressive disorders including major depressive episode both current and past, and dysthymic disorder; (3) attention deficit disorder with and without hyperactivity, and residual forms of the disorder; (4) conduct and oppositional disorder ; and (5) eating disorders including bulimia and anorexia nervosa. The prevalence of eating disorders will be reported in a separate paper. A copy of the modified DISC-C and the delinquency measure as well as some pyschometric properties of the DISC-C may be obtained from the authors. Social competence. At age 15, each interview with the adolescents was begun by asking questions concerning their family, friends, school, clubs, sports and activities , and employment. Parent and peer attachment was assessed with scales developed by Armsden and Greenberg (1987) . A measure of school involvement was obtained from the rating scale devised by Elliott and Voss (1974, p. 229) , together with the age at which the adolescent intended to leave school. A series of questions was asked concerning whether or not they talked to others about their problems , and, if so, to whom they talked. Finally, each adolescent completed a 22item checklist of "strengths," consisting of words or phrases describing positive aspects of how he or she saw themselves. Examples of items include "kind," " independent ," "good sense of humor," and "attractive." Seven composite scores were used to make up a social competence index. These scores came from the assessments of parent attachment, peer attachment , school involvement, activities and leisure, support and coping, and strengths. These were scored as 0, 1, and 2 for low, medium , and high levels of competence based upon distributions of scores for each measure. Part-time work was scored as 0 or 1, allowing for a potential range of scores from 0 (indicative of very poor social competence) to 13 (very high social competence). It should be emphasized, however, that the measure of social competence is based upon the adolescent's own perception (McGee and Williams, submitted for publication). Parent questionnaire. The parents completed the Revised Behavior Problem Checklist (RBPC) (Quay and Peterson, 1987) as well as other questionnaires relating to family background. The RBPC is a 77-item scale scored for subscales assessing conduct disorder (CD), socialized aggression, anxiety-withdrawal (AW) , attention problem-immaturity (AP), motor excess, and psychotic behavior. In addition to the RBPC, the parents were asked to describe the following: any significant behavioral or emotional problem l.Am .Acad. Chi/dAdolesc . Psychiatry, 29 :4, luly 1990

they believed their son or daughter had, and how long they had been aware of such problems; any police contact their son or daughter may have had; and any help sought for their son or daughter including referrals to medical, social welfare, or educational agencies over the past 2 years . To examine the relationship between family adversity and disorder , the following measures were chosen from the parent questionnaire : family SES, family size, parental separations, solo parenting , maternal mental health assessed by a 21-item depression questionnaire (McGee et al., 1983b), and a measure of perceived family social support, the family relations index based upon the cohesion, expressiveness, and conflict subscales of the Family Environment Scale (Holahan and Moos, 1983). These six measures were also combined into a six point summary index of family adversity. Procedure The adolescents were assessed as closely as possible to their fifteenth birthdays, usually within a month. The majority of interviews were carried out at the Dunedin Unit (about 90%) by F.P., M.F., and R.M . Before each interview, the adolescent was assured of the confidentiality of the interview. Procedures were set in place in the interview to allow for consultation with the parent(s) and referral for counselling if sought by the adolescent. The parent questionnaires were mailed out about 2 weeks before the appointment at the unit, together with an explanation of the assessments and a consent form for the parent to sign . Written consent from the adolescent was also obtained. The parent questionnaire was returned on the day of the appointment; it was not available to the interviewer before the interview . The assessments were carried out between February 1987 and May 1988. Following the procedure outlined by Anderson et al. (1987), a sample of 66 interviews by MF and FP were audiotaped during the year and rescored by RM to give some indication of interrater reliability. Kappa for overall identification of disorder was K = 0 .87 , a value comparable to the interrater reliability of K = 0.86 at age 11. In addition, the scoring for all interviews was double checked and "case" discussions were held where there were doubts regarding the appropriate scoring of items. Identification of Disorder There does not appear to be a single "best way" to use adolescent and parent report to identify disorder. For example, there are limits in the extent to which parents and their adolescent children can be expected to agree . This raises the question as to where the emphasis in terms of source of information should lie. A starting point was to define replicable decision rules which would allow the adolescent and parent information to be used together to identify disorder. Reich and Earls (1987) have suggested that the child's report, particularly in the case of older children, may provide the best source of data for diagnosis, and that other sources of information can be regarded as confirming or elaborating the child's report. Edelbrock et al. (1985) have reported relatively high test-retest reliabilities for the 613

MCGEE ET AL.

DISC-C with adolescents aged 14 to 18, so that an emphasis on the report of an adolescent appears justified. In this study, identification of disorder was based in the first instance upon the adolescent's self-report meeting DSM-III criteria. Following Anderson et al., only "2" responses ( a definite "yes") to the DISC-C questions were used to indicate presence of criterion symptoms. The parent report was then used to "confirm," using Reich and Earls' terminology, the adolescent report of disorder. (Teacher reports were not available at the age 15 assessment.) For the majority of DSM-III disorders, the criteria for identification, for example, number of symptoms required, are specific. However, the authors found it necessary to develop several operational definitions in identifying some particular disorders. For attention deficit disorder-residual type, the presence of at least three attentional/impulsive symptoms at age 15 was specified. In the case of all attention deficit disorders, these individuals had to meet the additional criterion of having already been identified as having the disorder by age 7 (McGee et al., 1983a; Anderson et al., 1987). For phobic disorders, it was specified that the fear had to "cause problems" for the individual, "stop them from doing things they want to do," and "stop them from doing things with others, " before identifying it as a phobia. Social phobia required the additional qualification of "worrying about making mistakes in front of others" and "worrying about other people your age laughing at you." In the case of nonaggressive conduct disorder, it was specified that the adolescent had to show symptom(s) from at least two of the following: (1) truancy-suspensions from school; (2) running away overnight; (3) serious lying; (4) substance use; and (5) nonconfrontational stealing. The disorder was identified as "mild" where two of the foregoing were present, "moderate" where three were present, and "severe" where four or all five were present. For aggressive conduct disorder, the adolescent had to show either theft involving confrontation with the victim or at least two behaviors relating to fighting, carrying or using a weapon, setting fires, damaging property, or breaking and entering. For both types of conduct disorder, only behaviors scored "2" (occurring 3 or more times) were counted. The RBPC and additional parent questions did not supply complete diagnostic criteria for DSM-III disorders. Rather, the general nature of the information obtained from parent report was used to confirm the adolescent self-report. The following six "rules" for confirmation were developed. First, disorder was regarded as confirmed if the parent score for the relevant subscale of the RBPC fell at or above 1.5 standard deviations from the mean for males or females, respectively. The relevant disorders, RBPC subscales and cutoffs are shown in Table 1. The RBPC-CD scale contains a mix of items relating to fighting, bullying and irritable behaviors, and oppositional behaviors. A shorter subscale was constructed to obtain a measure of oppositional behaviors made up of the following items: staying out, tantrums, disobedient, negative, impertinent, argues, persist-nags, and refuses directions. This scale was used for the confirmation of nonaggressive conduct and oppositional disorders only. 614

1. DSM-Ill Disorders at Age 15 and Revised Behavior Problem Checklist" (RBPC) Confirmation "Rules"

TABLE

Cut-Off Type of DSM-III Disorder 1. Anxiety 2. Depression 3. Attention deficit (and residual) 4. Aggressive conduct

5. Nonaggressive conduct and oppositional a b

RBPC Subscale

M

F

Anxiety-withdrawal Anxiety-withdrawal Attention problemimmaturity Conduct disorder Socialized aggression Conduct disorder Socialized aggression Oppositional

9 9

10 10

13 17 6 17 6 7

lO*b 15*b 6 15 6 7

Quay and Peterson, 1987. RBPC subscale showed significant sex difference.

The cutoff scores in Table 1 identified about the upper 10% of the relevant distributions on each scale. In addition, the cutoff scores are comparable with mean values given in the RBPC manual for various samples of adolescents with emotional, behavioral, and delinquent disorders. In some instances, the parent RBPC indicated a disorder dissimilar to that indicated by adolescent self-report. For example, there may have been a high score on AW or AP where the adolescent report suggested conduct disorder. This was not considered confirmation. The second "rule" for confirmation was a high total RBPC score (43 or more for boys and 39 or more for girls at the 1.5 standard deviation cutoff) and parent report of symptom(s), scored "2," from the relevant subscale. Third, adolescent self-report could be confirmed by parent report of a significant behavioral or emotional problem, where the problem mentioned was a criterion symptom(s) for the disorder. Fourth, the self-report could be confirmed by parent report of referral to agencies for help. Fifth, conduct disorders could be specifically confirmed by parent report of police or judicial contact. Sixth, there were a few instances where the diagnostic criteria were met by combining the symptoms on the adolescent and parent report. Results Prevalence of DSM-III Disorder

A total of 962 adolescents were interviewed with the DISC-C, while RBPC and parent reports were available for 943 (483 boys and 460 girls). The prevalence rates are based upon those 943 adolescents with both self- and parent-report. In identifying disorder, DSM-III exclusionary criteria were used where appropriate, e.g., oppositional disorder was not identified when there was a coexisting conduct disorder. Multiple disorders were assigned where appropriate. A total of 207 adolescents or 22% of the sample had one or more disorders. Overall, there were significantly more females with disorder than males (25.9% versus 18.2%); the ratio of females:males was 1.4:1, a significant sex difference with X2 (ldf) = 7.61, p < 0.05. There was a total of 267 identified disorders and Table 2 gives the prevalence of each disorder. J. Am.Acad. Child Adolesc. Psychiatry, 29:4, July 1990

DSM-III DISORD ERS IN ADOLESCENTS T ABLE

2. Prevalence of Individual Disorders by Sex

Disorder

F

M

F:M

Prevalence %a

Overanxious Separation anxiety Simple phobia Social phobia Major depr essive episode: current Major depr essive epi sode: past Dysthymia Attention deficit diso rder Attention deficit disorder: residual Condu ct disorder: aggressive Conduct disorder: nonaggressive Oppositional

36 12 25 4

20 7 9 6

1.9:1 1.8:1 2.9 :1 0.7:1

5.9 2.0 3. 6 I.l

7

4

1.8:1

1.2 ± 0. 7

14

4 4

3.7:1 2.6:1

1.9 ± 0.9 I.l ± 0.7

0.4:1

2.1 ± 0.9

10

± ± ± ±

1.5 0.9 1.2 0.7

3 5

11

0

15

34 12

20 4

1.6 ± 0.8 1.8:1 3. 1:1

5.7 ± 1.5 1.7 ± 0.8

Prevalences are shown with approximate 95% confidence intervals (Hays, 1969).

a

The most prevalent disorder was overanxious disorder , and the most common symptoms were related to exams or tests at school , performance at sports , and what other people think, particularly in social situations . The next most prevalent disorder was nonaggressive conduct disorder. Based on the definitions outlined above, 31 were identified (3. 3% of the sample) with " mild" conduct disorder; 13 (1.4 %) with "moderate" conduct disorder ; and 10 (1.0%) with " severe" conduct disorder . The most frequent combination of nonaggressive, conduct disorder behaviors was truancy and substance use, most typically alcohol and cannabis. About half of these 54 adolescents reported police contact. It is of note that there were more girls than boys with nonaggressive conduct disorder , especially in the " severe" category where there were eight girls and two boys. However, 11 of the 15 boys with aggressive conduct disorder would also have fulfilled the criteria for nonaggressive conduct disorder. The third most prevalent disorder was simple phobia and the most common of these fears related to speaking in front of the class, heights , aeroplanes, and being in water. All other disorders had prevalences of about 2% and below. The only disorders to show a predominance of males were attention deficit disorder and the residual form of this disorder, aggressive conduct disorder and, to a slightly lesser extent, social phobia . For most other disorders, there were about twice as many or more girls than boys. Of the 207 adolescents with disorder , 52 or about one in four had two or more DSM-ll/ disorders. The overlap among the four general categories of anxiety, depressive, conductoppositional , and attention-deficit disorders is depicted in Figure 1. The greatest degree of comorbidity was present in the case of depressive disorders ; almost two-thirds of the 40 adolescents with a depressive disorder had a coexisting disorder(s) from one or more of the other categories of J .Am.Acad. Child Adolesc . Psychiatry, 29:4, July 1990

disorder. The least overlap was in the case of conduct and oppositional disorder , and, where there was comorbidity, it was more frequently with a depressive disorder. Finally, there were seven adolescents with three or more disorders, most typically conduct disorder and/or multiple anxiety and depressive disorders . Social Competence across Types of Disorder It was not possible to examine social competence as a function of both type of disorder and parental confirmation of disorder , owing to small cell sizes. Consequently, the primary analysis examined competence across type of disorder , initially combining both confirmed and nonconfirmed disorders. Based upon the representation of disorders in Figure 1, 10 groups were formed . These were: a multiple disorder group comprizing adolescents with attention deficit disorder and/or conduct disorder, in comb ination with anxiety or depressive disorders; a conduct disorder-aggressive group; a conduct disorder-nonaggressive group ; an oppositional disorder group ; an attention deficit disorder-residual type group; a depressive disorder group ; a depressive plus anxiety disorder group; a multiple anxiety group; an anxiety disorder group (overanxiety or separation anxiety) ; and a phobic disorder group . Each group was compared with the no disorder group in a series of a priori comparisons (adjusted, p < 0.005 for each contrast ) on the index of social competence . The mean scores are shown in Table 3. These comparisons indicated that the multiple disorder, conduct and oppositional disorder, and attention deficit residual disorder groups each had a significantly lower mean social competence score than the no disorder group , with F (1,932) ;::: 7.87, p < 0.05. None of the depression or anxiety disorder groups differed significantly from the no disorder group. Table 3 also shows the proportion in each group scoring in the range 0 to 9 (approximately the lower 25% of the distribution of competence scores). These results

Anention-deficit Disorder

Oonouct- Opposit ional Disorder

Anxiety Disorder

Depressive Disorder

•

Onecase had an additional depressive disorder

.~

Thesecaseshad twoor moreanxiety disorders

FIG. 1. Overlap among the four major domains of disorder at age 15: attention-deficit, anxiety , conduct-oppositional, and depressive disorders.

6/5

MCGEE ET AL. T ABLE

3. DSM-III Disorder and Social Competence at Age 15 Low Competence

Type of Disorder

N

Multiple CD-ag gressive CD-nonaggressive Oppo sitional ADD- residual Depression Depre ssion + anxiety Multipl e anxiety Anxiety Phobia No disorder

26 13

Note: CD

=

N

Prop ortion

7.8 8. 1 8.8 8.9 9.0

19

0.73

9 22 7 8

0. 69 0.59 0.54 0.67

9.3

6

0.40

II 15 46

9.4 10.4 10.5

3 3

0 .27 0 .20 0 .26

19 736

10.6

37 13 12 . 15

12 4 173

10.7

conduct disorder ; ADD

=

0.21 0.23

attention deficit disorder.

reflected the mean scores in each group. In the foregoing "externalizing" disorder groups, 64% overall had low social competence scores; for the " internalizing" disorder groups, 26% had low competence scores, a proportion similar to the 23% in the remainder of the sample. Parent Confirmed Disorders About half of those adolescents with disorder had the disorder confirmed by parent report: 9.5% of the males (N = 46) and 10.9% of the females (N = 50) had one or more confirmed disorders , a nonsignificant sex difference. This is in contrast to 8.7 % of the males and 15.0% of the females with nonconfirmed disorder , a significant difference. The prevalences of confirmed disorders were as follows: 3.3% for anxiety disorders with female :male sex ratio of 3.0:1; 2.0 % for depressive disorders with female:male ratio of 2.2: 1; 4.7% for conduct and oppositional disorders with female:male ratio of 0.8 :1; and 2.1% for attention deficit disorder with female:mal e ratio of 0.4: 1. (All cases of attention deficit disorder were confirmed by parent report.) Overall, the parents confirmed about half of all adolescent reported conduct-oppositional disorders, but less than one third of adolescent reported anxiety-depressive disorders. It is possible that parents were simply confirming ' 'more severe" instances of self-reported disorders. To examine this question, the authors compared the DISC-C symptom scores of anxiety , depression, inattention, and conduct (Williams et aI., 1989), of those adolescents with confirmed and nonconfirmed anxious , depressive, and nonaggressive conduct disorders. This involved a series of 2 x 2 (sex x confirmation) analyses of variance for the three foregoing types of disorders. There were no significant differences in symptom severity for confirmed and nonconfirmed anxious, depressive, and nonaggressive conduct disorders, p < 0.05. In the case of aggressive conduct disorder, those boys with confirmed disorder had significantly higher total self-reported conduct disorder scores than those with nonconfirmed disorder. The respective means were 30.7 and 16.7, t (13) = 2.36, p < 0.05 . Earlier research from the Dunedin study indicated that

616

parental (primarily maternal) perception of problem behaviors varied as a function of background factors such as maternal depression , perceived family social support, and SES (McGee et aI. , 1983a,b) . Consequently, the authors were interested primarily in the differentiat ion between the family backgrounds of those adolescents with parent confirmed disorder and those with self-reported but nonconfirmed disorder. Table 4 shows the results for the six measures comprising the index of family adversity: low SES , solo parenting, large family size, parental separations, perceived family support measured by the family relations index (FRI), and maternal depression. Only the measures of parental separations, the FRI, and maternal depression showed overall significant differences among the groups. Post-hoc analyses indicated that for these measures, the parent-confirmed disorder group differed significantly from the no disorder group . The former showed over twice the rate of separations and the mothers reported lower FRI scores and higher depression scores . There were no significant differences between the nonconfirmed and no disorder groups. The last analysis to be reported here was intended to develop a more general model of the parental confirmation of disorder. For this analysis, a logistic regression model was used to examine differences between the parent-confinned and nonconfirmed groups (Fienberg, 1978).The model evaluated the effects of the following variables: sex of adolescent, maternal depression, family social support (FRI), separations, high family adversity, externalizing and internalizing symptom scores, and social competence . Significant effects were found for maternal depression , the FRI measure of family social support, and adolescent social competence (p < 0 .05). It may be noted that exclusion of maternal depression made relatively little difference to the model, suggesting family social support and adolescent social competence were the more important variables. Help Sought In the overall sample, parents reported referral for some kind of help for 11.8% of the boys and 13.7% of the girls, a nonsignificant sex difference. In addition to parent reports of help seeking, the adolescents were also asked about their own help seeking. In the case of the girls, 15% had sought help (primarily from teachers and school counsellors) compared with 9% of the boys, a significant difference with X2 (ldf) = 8.22, p < 0.05 ). Help had been sought (by self or parent) from psychiatric services, medical practitioners, social workers, school counsellors, or teachers for 46 of the 96 adolescents with parent confirmed disorder (48%). Many reported multiple instances of help seeking. Of those adolescents with nonconfirmed disorder , 20% of the girls and 7% of the boys reported seeking help for their problems, percentages similar to those in the remainder of the sample. Finally, the adolescents were asked about taking medication or other drugs or alcohol to make them feel better because they felt " so bad or upset." Only six adolescents reported taking prescription medicine. About 6% of the girls reported using nonprescription drugs/alcohol specifically to help them feel better; only 1% of the boys reported this, X2 l .Am.Acad . Child Adolesc .Psychiatry , 29:4 , luly 1990

DSM-III DISORDERS IN ADOLESCENTS TABLE

4. Family Adversity Measures and Disorder at Age 15 Group

Measure

Parent-Confirmed (N

Low SES Solo parent Large family Separations Family Relations Index Mother's depression

* Test-statistic

Non-Confirmed

= 96)

(N

19% 16% 3% 8% 15.8 4.3

significant, p < 0.05 (corrected a

= 111) 18% 20% 7% 2%

18.9 2.8 =

No Disorder

Test Statistic

(N = 736)

14% 13% 5% 3% 19.5 2.6

x2 (2dfJ = X2 (2dfJ = X2 (2dfJ = X2 (2dfJ = F(2, 928) = F(2, 901) =

2.78 NS 4.72 NS 1. 72 NS 9.47* 33.53* 11.36*

0.05/6).

(1df) = 15.51, p < 0.05. Of the 35 adolescents reporting this type of drug use, 25 had an identified disorder.

Missing Data

There were 962 adolescents with DISC-C results but only 943 available parent reports. Nine of the 19 adolescents with missing parent reports had a self-reported disorder; three boys and one girl had aggressive conduct disorder; one boy and one girl had nonaggressive conduct disorder; one boy had oppositional disorder; one girl had overanxious disorder; and one other girl had dysthymic disorder. The boys with aggressive conduct disorder reported multiple police contact for carrying and using weapons, vandalism, assault, burglary, and drug use. All had court appearances and two were in the custody of the Department of Social Welfare at the time of interview, suggesting serious levels of problem behavior. The inclusion of these three boys would indicate an overall prevalence rate of 3.7% for aggressive conduct disorder in 15-year-old boys. Discussion Comparisons of the results of epidemiological studies are inevitably limited by differences in the coverage and assessment of disorders. Such differences may be quite marked, particularly in view of rapid changes being made in diagnostic systems. With respect to the present report, the authors are unaware of any studies using comparable decisions or rules for identifying disorder based upon self- and parentreport. However, the authors believe that this approach provides a reasonably coherent, replicable method of combining the two sources of data. It also needs to be stressed that adolescent self-report was based upon a modified shorter version of the DISC-C. The interview provided full criteria for DSM-III disorders but provided less opportunity in some instances for reporting additional criterion symptoms. If anything, this could have had the effect of underestimating the prevalence of particular disorders. On the other hand, the modifications to the DISC-C were based upon the psychometric properties of the individual questions so that the more reliable items were included in the briefer version. In addition, the use of parent reported criterion symptoms, where appropriate, may have gone part of the way to making up for some of the omitted questions. Overall, the present study found the prevalence of DSMIII disorders to be 18.2% of 15-year-old boys, and 25.9% l.Am.Acad. Child Adolesc. Psychiatry, 29:4, luly 1990

of 15-year-old girls. The combined prevalence rate of about 22% is quite consistent with estimates from other epidemiological studies, suggesting that about one in every five adolescents has a recognizable mental health disorder. If, as Anderson et al. (1987) suggest, the term "disorder" is restricted to instances where there is agreement between different sources, then about 10% of the sample had a parent confirmed disorder. The most frequently occurring disorders were anxiety disorders. Nearly half of those adolescents with disorder had some form of anxiety disorder and about half of those had overanxious disorder, a proportion reflected in clinic referred samples of anxious adolescents (Last et al., 1987). Furthermore, many of those with overanxious disorder (26/ 56) had a concurrent disorder, primarily an anxiety or depressive disorder. The results suggest a relatively high degree of comorbidity in the case of anxiety disorders in adolescence. The finding of an overall female predominance for anxiety disorders is generally consistent with results in adult populations (Reich, 1986). It also agrees with the findings of Rutter et al. (1976) in the adolescent follow-up on the Isle of Wight where large numbers of girls reported emotional disorders generally not confirmed by parent report. Such a finding raises the issue as to whether such selfreports reflect a "real" mental disorder. However, as Rutter et al. point out and the authors' own experience confirms, these adolescents were reporting some degree of personal suffering or unhappiness. What is in doubt is the clinical significance or degree of disability associated with such anxiety disorders. Certainly, the present results indicate that anxiety was not generally associated with marked impairments in social competence. Elsewhere, however, it has been reported that anxiety disorders are associated with parental perceptions of disability (McGee and Stanton, 1990). Overall, some 9% of the sample reported conduct or oppositional disorder. While DSM-III-R has combined earlier criteria for aggressive and nonaggressive DSM-III subtypes, there were clear sex differences associated with the nature of the disorder. Only the boys showed aggressive conduct disorder and nearly all of these boys fulfilled the criteria for nonaggressive disorder as well. More girls, on the other hand, had the nonaggressive subtype most typically associated with truancy and alcohol/drug use. While this result was somewhat surprising, comparison of individual delinquent behaviors at age 13 and 15 (Moffitt and Silva, 617

MCGEE ET AL.

1988) did suggest a relatively greater increase over time in the prevalence of truancy, underage drinking, and petty theft in girls. Finally, oppositional disorder was relatively infrequent, with a prevalence of 2%. However, one-third of all adolescents with nonaggressive conduct disorder also fulfilled the criteria for oppositional disorder , suggesting that the nonaggressive subtype was replacing the oppositional category. There have been few published studies of the prevalence of depressive disorders in adolescence (Angold , 1988). In equivalent age samples, estimates have ranged from less than 1% to over 30% of adolescents. Studies using interviews, however, have tended to produce lower estimates and a finding of a 4% prevalence rate is consistent with this. Reference to Figure 1 indicates that depressive disorders showed the greatest degree of comorbidity with other disorders. Almost two-thirds of those with a depressive disorder had a coexisting conduct or anxiety disorder. Kovacs et al. (1984) have similarly reported high rates of comorbidity in clinic referred children. Depressive disorders were more common in the girls, a finding consistent with the general pattern of age and sex differences in depression (Jorm, 1987). In the case of attention deficit disorder, DSM-ll/ suggested three characteristic courses into adolescence: persistence of the full disorder, persistence of attentional and impulsive symptoms, and recovery. Results in this study indicate that the first proposed course is relatively infrequent. The authors were able to follow-up 49 of the 51 children identified as having a pervasive attention deficit disorder at ages 7 and 11 (McGee et al. , 1983a; Anderson et al. , 1987). Of the 49, a third had the residual form of the disorder at age 15; only four adolescents continued to show the full disorder. Less than half showed recovery in the sense of absence of any disorder at age 15. While many adolescents were identified as having some form of DSM-ll/ disorder, there were clear differences among disorders in terms of associated impairments in social competence. In general, the externalizing disorders rather than the internalizing ones were associated with the poorest social competence. Adolescents with the former showed significantly lower levels of " involvement and attachment " to the social world. This significant association between disorder and social competence raises the question of the causal direction between the two. Elsewhere (McGee and Williams, submitted for publication), this issue has been examined in more detail and results suggest that in the case of 15-year-old boys, poor social competence follows as a consequence of externalizing type disorder. It does not appear to be the case that social competence in adolescence offers a kind of " protection" against mental health problems. Rather, social competence appears to have a more limited protective role in the persistence of disorder over time. The assessment of mental health disorder has been bedevilled by the often poor agreement between different sources of information . This is particularly so in the case of parent and child as informants. Results in this study indicate that less than half of those adolescents with disorder 6/8

had their disorder confirmed by parent report. As Reich and Earls (1987) suggest , however, high agreement is not a feasible goal as there must be a limit on the degree to which consensus may be expected. Perhaps a more realistic approach is to examine the possible factors that might determine agreement. In the present study , it was not generally the case that parents confirmed more severe self-reported disorders; a possible exception may be aggressive conduct disorder. The model in this report, comparing parent confirmed and nonconfirmed disorders , indicated that confirmation was more likely when the mother was depressed and perceived the family as low in social support, and the adolescent showed poor social competence. This suggests that characteristics of the parent, family, and the adolescent himself or herself determine whether the parent regards the child's behavior as being a significant problem. The interesting feature of this model is that parent confirmation was not related to type of disorder (externalizing versus internalizing), but rather to social competence, a fact highlighting the importance of this neglected variable in models of psychopathology . The current results suggest that for nearly half of those adolescents with confirmed disorder, their parents or they, themselves, had sought some kind of help. Indeed, many of these boys and girls had a long history of referral to services, particularly those with attention deficit problems. In one sense, then, such a finding of at least a high recognition of disorder is encouraging. Furthermore, in the total sample , many of the adolescents had been referred to or had sought help from their school counsellor. These findings suggest that in Dunedin at least, adolescents appear to have good access to services , although it remains unclear as to whether the adolescents are any better off for having used the available services. Nevertheless, many with disorder have not used these services for whatever reasons, and an important area of investigation will be to discover why those adolescents with apparently significant, parent-recognized disorders have not made use of these services. Few adolescents were currently receiving prescription medication for mental health problems . However, a disturbing fact was the relatively large number of adolescent girls, many with disorder, who reported self-medication with alcohol or other drugs to make themselves feel better . This finding , together with the fact that many adolescents reported low levels of social support, suggests that significant numbers of adolescents have poor coping skills. This appears to be a good opportunity for intervention. A final comment relates to how these findings bear upon what are often stereotyped views of adolescence as a developmental phase. For example, Offer et al. (1981) have reported how mental health professionals have a view of adolescence as a developmental period of turmoil and potential psychopathology , a view not shared by adolescents themselves. The authors' findings support those of Rutter et al. (1976), indicating that the concept of "adolescent turmoil" as an inevitable consequence of this developmental period is perhaps more fiction than fact. Most of the adolescents in the sample did not have a mental health disorder. Depressive disorder was relatively infrequent, and only one l .Am.Acad. Child Adolesc.Psychiatry, 29:4 , luly 1990

DSM-III DISORDERS IN ADOLESCENTS

in 10 reported significant periods of depressed or anhedonic mood. While anxiety disorders were more common, overall, most adolescents did not report high levels of emotional symptoms. However, a significant minority of 15-year-olds did have a disorder, poor social competence , and inappropriate coping skills. It is this group which should be a target for prevention and treatment. In summary, this study showed that in a population sample of 15-year-olds about 22% had one or more DSM-lll disorders . About half of these adolescents had their disorder confirmed by parent report . The next phase of the authors' research has been to examine the persistence of disorder from preadolescence through to the adolescent period, to identify predictors of adolescent disorder, and to determine protective factors that prevent disorder in otherwise vulnerable individuals. This is the topic of a companion paper (McGee et aI., unpublished). References Anderson , 1., Williams , S., McGee , R. & Silva , P. A. (1987 ), DSMIII disorder s in pre-adol escent children: prevalence in a large sample from the general population . Arch . Gen. Psychiatry, 44:69-76. Angold , A. (1988 ), Childhood and adolescent depression: I. epidemiological and aetiolo gical aspects. Br. J . Psychiatry , 152:601617 . Armsden , G. G. & Greenberg, M. T. (1987) , The Inventory of Parent and Peer Attachment: individual differences and their relat ionship to psycholo gical well-being in adolescence. Journal of Youth and Adolescence, 16:427--454. Bird, H. R. , Canino , G., Rubio-Stipec , M . et al. (1988), Estimates of the prevalence of childh ood maladjustment in a commun ity survey in Puert o Rico. Arch . Gen. Psychiatry, 45: 1120-1126 . Blechman, E. A., Tinsley , B. , Carella, E. T . & McEnroe , M . J . (1985) , Childhood competence and beha vior problems. J . Abnorm . Psychol ., 94:70-77 . Cohen , P., Velez, N. Kohn , M. , Schwab-Stone, M & Johnson , J . (1987), Child psychiatric diagnosis by computer algorithm: theoretical issues and empiric al tests . J. Am . Acad. Child Adolesc. Psychiatry, 26:631-638. Costello , A., Edelbrock, C. , Kalas, R., Kessler , M. & Klaric, S. A. (1982), Diagnostic Interview Schedule for Children (DISC) . Contract No . RFP-DB-81-0027 . Bethesda, MD: National Institute of Mental Health . Edelbrock , c., Costello, A. J., Dulcan , M . K. , Kalas , R. & Conover, N. C. (1985) , Age differences in the reliability of the psychiatric interview of the child. Child Dev., 56:265-275. Elley , W . B. & Irving , J. C . (1972), A socio-economic index for New Zealand based on levels of education and income from the 1966 census . New Zealand Journal of Educational Studies, 7:155-167 . Elliott , D. S. & Voss , H. L. (1974) , Delinquency and Dropout. Lexington, MA : D . C . Heath & Co. Felsman , J . K. & Vaillant, G. E. (1987), Resilient children as adults: a 40 year study. In: The Invulnerable Child. eds. E. J. Anthony & B. J. Cohler. New York : Guilford Press. Fienberg , S. E. ( 1978), The Analysis of Cross-Classified Categorical Data. Cambridge, MA : MIT Press. Frost , L. A., Moffitt, T. E. & McGee , R. (1989) , Neurops ychological correlate s of psychopathology in an unselected cohort of young adolescents . J . Abnorm. Psychology, 98:307- 313. Garmezy, N. (1971) , Vulnerabilit y research and the issue of primary prevention. Am . J. Orthopsychiatry, 41:101-116.

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Hays, W . L. (1969 ), Statistics. London: Holt, Rinehart & Winston. Holahan , C. J. & Moo s, R. H. (1983) , The quality of social support: measures of family and work relationships . Br. J. Clin . Psychol., 22:157-162. Jorm , A. F. (1987), Sex and age differences in depression: a quantitative synthesis of publi shed research. Aust . N . Z. J . Psychiatry, 21:46-53 . Kovacs , M ., Feinber g, T . L., Crou se-Novak, M . A., Paulauskas, S. L. & Finkelstein, R. (1984 ), Depres sive disorders in childhood: I. a longitudinal prospective study of characteristics and recovery. Arch. Gen. Psychiatry , 41:229-237 . Krupinski , J . , Baikie , A. G ., Stoller, A. , Grave s , J. , O'Day , D . M . & Polke , P. (1967 ), A community health survey of Hayfield , Victoria . Med. J . Aust., 1:1204-1211. Last , C. G., Hersen, M . , Kazdin, A. E. , Finkelstein, R . & Strauss, C. C. (1987), Comparison of DSM-III separation anxiety and overanxious disorder: demographic characteristics and patterns of comorbidity . J. Am. Acad. Child Adoles c. Psychiatry, 26:527-531. Leslie , S. A. (1974) , Psych iatric disorder in the young adolescents of an industrial town . Br. J. Psychiatry , 125:113-124. McGee , R. & Stanton, W . (1990 ) , Parent reports of disability among thirteen year olds with DSM-III disorders. J . Child Psychol. Psychiatry, in press. - - Silva , P. A. & Willi ams, S. M . (1983a), Parents ' and teachers' percepti on of behav ior problems in seven year old children . Except . Child, 30:151-161. - - William s, S. , Kashan i, J . H. & Silva, P . A. (1983b ), Prevalence of self-reported depre ssive symptoms and associated social factors in mothers in Dunedin. Br . J . Psychiat ry, 143:473--479. Moffitt , T . E. & Silva, P . A. (1988), Self-reported delinquency: results from an instrument for New Zealand. Australian and New Zealand Journal of Criminology , 21:227-240. New Zealand Department of Statistics (1983 ) , New Zealand Yearbook , 1983 . Wellington: Government Printer. Nunnall y , J. C. (1967), Psychometric Theory. New York : McGraw Hill . Offer , D. , Ostrov, E. & Howard , K. I. (1981), The mental health professional's concept of the normal adolescent. Arch . Gen . Psychiatry, 38:149-152. Offord , D. R. , Boyle , M . H. , Szatmari, P. et al ( 1987), Ontario Child Health Study : II. six month prevalence of disorder and rates of service utilisation . Arch. Gen . Psychiatry, 44:832-836 . Quay , H. C. & Peterson , D. R. (1987 ) , Manual for the Revised Behaviour Problem Checklist. Miami: Authors. Rapoport , J. L. (1986), Annotation: childhood obsessive compulsive disorder. J. Child Psychol . Psychiatry , 27:289-295. Reich , W . (1986), The epidemiology of anxiety . J . Nerv . Ment. Dis ., 174:129-1 36. Reich , W. & Earl s, F. (1987), Rules for making psychiatric diagnosis in children on the basis of multiple sources of information: preliminary strategies. J. Abnorm. Child Psychol. , 15:601-616 . Rutter , M. , Tizard , J . Yule, W. , Graham, P. & Whitmore , K. (1976 ), Isle of Wight Stud ies , 1964-1974. Psychol . Med. , 6:313-332 . Silva , P. A. (1990 ), The Dunedin Mult idisciplinary Health and Development Research Study : a fifteen year longitudinal study . Paediatric and Perinatal Epidemiology, 4:96-127. Werry , J . S. (1988), Letters to the editor: in memoriam - DSM-III. J. Am . Acad. Child Adoles. Psychiatry, 27:138-139. William s, S., Anderson, J . , McGee, R. & Silva, P. A. (1990) , Risk factors for behavioral and emotional disorder in pre-adolescent children . J . Am . Acad. Child Adoles . Psychiatry , 29:413--419. - - McGee , R. , Anderson , J. & Silva , P. A. (1989 ), The structure and correlates of self-reported symptoms in ll-year-old children. J. Abnorm. Child Psychol. , 17:55-71. Zimmerman, M . (1988), Why are we rushing to publi sh DSM-IV? Arch. Gen. Psychiatry, 45 :1135-1138.

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