Substance Abuse Prevalence and Comorbidity with Other Psychiatric Disorders among Adolescents with Severe Emotional Disturbances PAUL E. GREENBAUM, PH.D., MARK E. PRANGE, PH.D., ROBERT M. FRIEDMAN, PH.D., AND STARR E. SILVER, PH.D. Abstract. Among 547 adolescents with serious emotional disturbances, ages 12 to 18, this study assessed (I) prevalence of DSM-IlI substance use disorders (i.e., alcohol and marijuana abuse/dependence), and (2) comorbidity with DSM-IlI Axis I disorders. Factors of age, sex, state location, and type of treatment program also were examined. Data were analyzed by logistic regression. Significant factors (p < 0.05) associated with severe alcohol or marijuana abuse/dependency diagnoses included (I) residential mental health treatment program, 2.37 Odds Ratio (OR); (2) conduct disorder diagnosis, 2.18 OR; (3) depression diagnosis, 1.75 OR; (4) states, 1.43 OR; (5) age, 1.29 OR; and (6) a depression x facility interaction, 1.91 OR. l. Am. Acad. ChildAdolesc. Psychiatry, 1991,30,4:575-583. Key Words: dual diagnosis, adolescents, substance abuse, serious emotional disturbance, comorbidity.

Many individuals suffering from serious psychiatric disorders also have serious substance-use problems. Such dually disordered individuals represent a sizable proportion of both substance-use and psychiatric patient populations. Osher (1989) has estimated that half of all psychiatric patients can be classified as having symptoms of chemical dependency, with a similar proportion of those with chemical dependency having psychiatric symptoms. Dually disordered patients have been reported as more problematic in terms of assessment, treatment, and outcome than those with only one disorder (Gerstley et al., 1990; Lehman et al., 1989; Lett, 1988; Menicucci et al., 1988; Osher and Kofoed, 1989; Schuckit, 1983), partly because of the additional complexity that two rather than one disorder represent and partly because of the specific relationship between substance abuse and other psychiatric disorders (Bukstein et a1., 1989). Unfortunately, no simple univariate relationship between substance abuse and other psychiatric disorders has been found. Instead, multiple and heterogeneous relationships have been reported. Substance abuse may mimic, precipitate, exacerbate, be an effect of, or be independent of nonsubstance disorders. Such clinical heterogeneity has made initial assessment and subsequent treatment more difficult. Moreover, additional complexity may

Accepted February 19, 1991. From the Research and Training Centerfor Children's Mental Health, Florida Mental Health Institute.

enter into the dual disorder relationship as specific patterns may vary, either among individuals with the same psychiatric illness or within the same individual over time. Notwithstanding the inherent complexity in isolating these relationships, recent studies have sought to increase understanding of substance use comorbidity. Helzer and Pryzbeck (1988) have reported that among adults in the general population, alcohol and drug disorders were the first and third most prevalent lifetime DSM-III disorders and that the risk for alcoholism was 2.8 times greater (2.8 odds ratio [OR]) among those with other psychiatric disorders. Among clinical populations, the rate of dual disorders also has reflected greater than expected risk for substance abuse; "as many as 40% of persons diagnosed with a psychiatric illness may also have a serious drinking problem" (Lett, 1988, p. 16). Similarly, studies of adult substance abusers have reflected a tendency for increased risk of cooccurring psychopathology (Hesselbrock et al., 1985; Ross et al., 1988). Among adolescents identified with serious emotional disturbances, the risk for comorbid substance-use disorder has been considered to be substantial. However, little research on substance abuse/dependency prevalence has been conducted with this population. A noteworthy exception has been Elliot and his colleagues' (1989) community sample study of youth with multiple problems of substance use, delinquency, and mental health. Using a global measure of mental health problems, they found that adolescents with serious emotional problems tended to have higher prevalence rates for problem substance abuse and mental health

Supported by Gram H133B90004-01 from the Nationallnstitute on

service utilization. The highest prevalence of alcohol, mar-

Disability and Rehabilitation Research and the National Institute of Mental Health. The authors thank Eric C. Brown for assistance in data analysis and Sharon P. Lardieri, Mike Bevill, Aaron Brie, Al Duchnowski, Maria Duchnowski, Marvin Eisen, Kelly Enzor-Kise, Sue Greer, Bob Haas, lini Hanjian, Holly Hons, Krista Kutash, and Bradley Sickles for assistance in data collection. Reprint requests to Dr. Greenbaum, Research and Training Center for Children's Mental Health, Department ofEpidemiology and Policy Analysis, Florida Mental Health Institute, University ofSouth Florida, 13301 Bruce B. Downs Blvd., Tampa, FL 336/2-3899. 0890-8567/91/3004-0575$03.00/0© 1991 by the American Academy of Child and Adolescent Psychiatry.

ijuana, polydrug, and problem substance use was found among adolescents with both serious delinquency and emotional problems. ' From a clinical perspective, writers have hypothesized that adolescent substance-use disorders are associated with most psychiatric disorders. In a recent review, Bukstein et al. (1989) cited affective disorders, conduct disorder and antisocial personality disorder, attention-deficit hyperactivity disorder, anxiety disorder, schizophrenia and psychotic symptoms, and eating disorders as related, either directly

J. Am. Acad. Child Adolesc. Psychiatry, 30:4, July 1991

575

GREENBAUM ET AL.

or indirectly through family history, with adolescent substance abuse. Determining the relative magnitude of substance-use problems among youngsters suffering from a variety of emotional and behavioral disorders would be an initial step in extending understanding of psychiatric comorbidity. Few data have been collected that examine this question. Recently, DiMilio (1989) found that among a relatively small group of adolescent substance abusers with concurrent mental health problems who were admitted to inpatient facilities for treatment (N = 57) conduct disorder, depression, and attention-deficit hyperactivity were more likely to cooccur than schizophreniform and anxiety disorders. The purposes of this study were to assess the following among a sample of youth identified as having serious emotional disturbances: 1) the prevalence of DSM-//I substance use disorders (i.e., alcohol and marijuana abuse/dependence) and 2) substance use comorbidity with DSM-III Axis I disorders (Le., conduct disorder, anxiety, depression, attention deficit, and schizophrenia). Additionally, factors of age, gender, state location, and type of treatment program (i.e., mental health residential vs. community-based special education) were examined and controlled for in analyzing prevalence and comorbidity. Method Subjects

The initial sample consisted of 812 youngsters, ages 8 to 18 years (mean, 13 years 11 months), who had been identified by either mental health or public school systems as having serious emotional disturbances in accordance with Public Law 94-142. The subjects were predominately white (70%), male (75%), and either resided in mental health facilities (46%) or were enrolled in community-based special education programs (54%). The age distribution of the sample was 8 to 11 years, 24.4%; 12 to 14 years, 39.8%, 15 to 18 years, 35.8%. The racial composition of the sample was 70% white, 22% black, 5% Hispanic, and 3% other minority (Le., Native American, Asian American). All subjects were paid volunteers who, after being informed of the study's purpose, agreed to participate. All participation was carried out within the ethical guidelines of the schools and residential centers involved. Procedure

Data were collected as part of the National Adolescent and Child Treatment Study (NACTS), a comprehensive 7-year longitudinal study designed to examine over time problems and outcomes of adolescents with serious emotional disturbances. NACTS drew a sample of seriously emotionally disturbed (SED) youth based on a stratified, multistage, cluster sampling design. Stratification was designed to yield approximately equal numbers of youth who were (I) served by mental health and special education programs; (2) in each age grouJr-8 to II, 12 to 14, and 15 to 18; and (3) of each sex. The sample was drawn in 1985 and contained 1,393 eligible youth aged 8 to 18 at the time of the initial interview. Of those eligible, 812 (58.3%) 576

agreed to participate, signed informed consents, and completed interviews. The resulting sample included subjects in all requisite conditions, although the numbers in particular strata were somewhat discrepant from the original design. As part of NACTS' initial data collection wave, six states (Alabama, Colorado, Florida, Mississippi, New Jersey, and Wisconsin), which represented the four geographic regions of the country, were selected. Along with geographic diversity, criterion variables for state selection included sociodemographic diversity, differences in the proportion of youth identified as emotionally disturbed, and services that were available. Obtaining cooperation from school and mental health authorities was a further restriction on state selection. Within each state, subjects from residential mental health and special education programs were identified by mental health facility and school administrators, respectively. At each of 121 sites, either all subjects meeting criteria were asked to participate or a subset of potential subjects was randomly selected. The study gathered in-depth information on adolescents' family characteristics, their psychological functioning, the services they received, and their outcomes over time. Instrument

During 1985 and 1986, face-to-face interviews of approximately 2 Y2 hours in duration were conducted with the subjects. Youngsters were administered the Diagnostic Interview Schedule for Children (DISC-C; Costello et aI., 1984). The DISC-C, a structured instrument containing 846 items, was administered by a trained interviewer, and yielded DSM-//I diagnostic disorders based on computerized algorithms. Derived diagnoses included 33 Axis I DSM-III diagnoses, including alcohol and marijuana abuse/dependency, and 22 standardized symptom scores that reflected extent and type of reported symptoms. Adjustment reactions were not included among the derived diagnoses because these disorders were not considered to be manifestations of either long-term or significant psychopathology. Other types of psychoactive drug use (e.g:, opiates, cocaine, amphetamines, barbiturates, heroin, hallucinogens, inhalants, etc.) also were assessed. However, as pathological use, impairment, and tolerance/withdrawal symptoms for these substances were not part of the DISC-C, no diagnoses for other drug disorders were derived. For each disorder, two levels of severity were assessed; mild/moderate (Le., level 1) and severe (i.e., level 2). Mild/ moderate criteria were created to reflect minimum thresholds for obtaining DSM-//I diagnoses. In contrast, the severe level reflected increased criteria and had been designed to be consistent with clinicians' diagnostic judgments so that false positive diagnoses would be minimized. For example, alcohol abuse diagnoses were assessed as mild/moderate in severity if a pathological pattern of use (e.g., drank every day and drank more than two or three glasses of wine or beer or hard liquor at a time) was present. A severe abuse diagnosis indicated that not only was there a pathological pattern of use that had a duration greater than 1 month, but impairment (e.g., alcohol-related problem with either school, police, family, or friends) also was present. Alcohol deJ.Am. Acad. Child Adolesc. Psychiatry, 30:4, July 1991

SUBSTANCE ABUSE PREVALENCE

pendence always was diagnosed at the severe level and indicated a pathological pattern of use or impairment and presence of either tolerance or withdrawal symptoms. A similar set of criteria was used for mild/moderate and severe marijuana abuse and severe marijuana dependency except that criteria for mild/moderate marijuana abuse used impairment rather than pathological use as the symptom. Other instruments including a semistructured interview assessing self-perceived problems and receipt of past and current services, Rosenberg's Self-esteem Scale, Slosson Intelligence and Oral Reading Tests, Arithmetic Subtest of the Wide Range Achievement Test, and Olson's Family Adaptability and Cohesion Evaluation Scale (FACES III) also were administered at this time but were not related to the present study. Reliability of the substance use and core Axis I psychopathology disorders were assessed by coefficient alpha calculated on symptom scores for the various disorders. All alphas were adequate and ranged from 0.71 to 0.94. Specifically, the following alphas were obtained: alcohol abuse/ dependency, 0.85; marijuana abuse/dependency, 0.84; substance abuse/dependency (i.e., combined alcohol or marijuana disorders), 0.89; conduct disorder, 0.93; anxiety, 0.94; attention deficit, 0.91; depression, 0.88; and schizophrenia, 0.71. Results

Among the 812 youngsters available for completing the DISC-C, 708 complete instruments were obtained. One hundred and four respondents did not provide usable interviews for the following reasons: not testable (N = 53), did not understand the questions or provided unreliable responses (N = 24), refused (N = 14), and logistical constraints (N = 13). Additionally, among youngsters ages 8 to 11, there was only one case of alcohol-use disorder and two cases of marijuana-use disorder. These low rates of occurrence made analysis of prevalence and comorbidity unfeasible for children younger than 12 years. Subsequently, analyses were based on youngsters ages 12 and older (N = 547). The mean age of these subjects was 14 years 11 months, with 52% enrolled in residential mental health treatment. Racial and gender compositions of this subsample were virtually identical to the total group of 812. The resulting data were analyzed in two ways. First, separate bivariate chi-square analyses were conducted on the prevalence of substance use disorders for each independent factor (i.e., Axis I DSM-III core disorders--conduct disorder, depression, anxiety, schizophrenia, attentiondeficit; age; sex; states; and facility). These analyses did not adjust for shared variance with any other independent factor and provided a descriptive picture of the unadjusted odds ratio of each factor's association with substance use. An OR of 1.0 indicates no relationship or independence of a factor with substance use. ORs less than 1.0 indicate a negative or inverse relationship of a factor with substl\nce use, while ORs greater than 1.0 indicate a positive or direct association with substance use. Logistic regression was the second technique used to analyze the data. These analyses provided (1) adjusted ORs to l.Am.Acad. Child Adolesc. Psychiatry, 30:4,luly 1991

control for shared variance among the multiple independent factors, (2) tests of two-way interaction terms, and (3) an overall test of how well the final regression model fit the data. A backwards elimination procedure was used to construct the final regression model and provide estimates of the adjusted ORs. Independent factors entered into the logistic regressions were age (12-14/15-18), sex, states, facility (mental health/special education), and Axis I DSMIII core disorders. Separate analyses were conducted at both mild/moderate and severe levels of diagnoses for alcohol, marijuana, and the combined category of alcohol or marijuana disorders. Initially, an independence model consisting of all main effects was tested. Subsequently, all two-way interaction terms were added to the main effects model, whereupon nonsignificant interaction terms were eliminated. Final multivariate regression models were tested for goodness offit, using a maximum likelihood chi-square test. The overall prevalence rates for youth ages 12 to 18 years were alcohol disorder-mild/moderate abuse and severe abuse/dependency, 11.0% and 10.1 %, respectively; marijuana disorder-mild/moderate abuse and severe abuse/dependency, 17.7% and 14.6%, respectively. There was a high degree of comorbidity between alcohol and marijuana use disorders. The OR for having either an alcohol or marijuana severe abuse/dependency disorder, given the presence of the other substance-use disorder was 14.2X, with 60% of those with severe alcohol abuse/dependency disorder having severe marijuana abuse/dependency disorder. Conversely, 41.25% of those with severe marijuana abuse/dependency disorder had severe alcohol abuse/dependency disorder. Perhaps not surprisingly, given the high degree of overlap between those having marijuana and alcohol disorders, analyses performed on the separate substance-use categories produced results similar to those for the combined category of alcohol/marijuana. Similarities between marijuana and alcohol users were explored further by discriminant function analysis. For each level of diagnostic severity, a discriminant function analysis, which included all of the independent factors in this study as predictors, found no significant mean differences on any predictor variable in discriminating among subjects who had only alcohol, only marijuana, or both diagnoses. Given the lack of significant differences in these analyses, the high proportion of subjects with cooccurring alcohol and marijuana disorders, and the increased stability of results based on the greater number of cases with either one or both disorders, the present report, in the interest of brevity, has presented results only for the combined categories of substance-use disorders (i.e., either alcohol or marijuana). Prevalence rates for substance-use disorder (i.e., either alcohol or marijuana) were 21.8% and 18.6% at mild/moderate and severe levels, respectively. Additionally, the prevalence rates of having used other psychoactive drugs were the following: amphetamines, 10.0%; hallucinogens, 8.8%; cocaine, 6.6%; barbiturates, 4.0%; inhalants, 2.0%; hashish, 1.8%; heroin, 1.5%; and opiates, 0.4%. Usage of these other drugs was significantly correlated (p < 0.01) with having a mild/moderate substance abuse (i.e., alcohol or marijuana) disorder. These correlations ranged from 0.48 577

GREENBAUM ET AL.

80

% WITH DISORDER r---------------------------------,

~ MODERATE _

SEVERE

60

40

20

o CD

ANX

DEPR

ADD

SCHZ

DRUG

POT

ALC

DSM-III DISORDER FIG. I. Prevalence of DSM-Ill disorders at moderate and severe levels among adolescents ages 12 to 18 (N = 547).

for hallucinogens to 0.12 for opiates. A similar pattern was found for severe substance abuse/dependency (i.e., r = 0.48 for hallucinogens to r = 0.13 for inhalants), except that opiate usage was not significantly correlated. Among severe DSM-III disorders that occurred within the sample, substance abuse/dependency disorder was the second most prevalent. Figure 1 graphically shows relative prevalence rates at both mild/moderate and severe levels for the five core nonsubstance diagnoses and alcohol, marijuana, and substance use (i.e., alcohol or marijuana) disorders. Chi-square analyses of substance abuse level 1 (mild/ moderate) diagnoses indicated that among tested variables, only schizophrenia and anxiety disorders were not associated with significantly greater rates of marijuana or alcohol disorders. Factors, in descending order, that were significantly associated with increased rates of substance abuse were the following: conduct disorder, states, depression, residential mental health placement, age, being female, and attention deficit disorder. A similar picture was found for level 2 (severe) alcohol or marijuana disorders, except that attention deficit and anxiety were associated with only mar-

578

ginally higher rates (p < 0.10) of substance abuse/dependency. For each factor, Table 1 shows the relative frequency of substance-use disorder between those with the factor versus those without the factor, the resulting chi-square statistic, and the unadjusted OR. In the analysis of state differences, initial chi-square statistics tested for overall differences among the six states at severe and mild/moderate levels, X2 (5, N = 547) = 25.32, p < 0.001; X2 (5, N = 547) = 28.03, p < 0.001, respectively. Follow-up chi-square statistics tested differences between all pairs of states, so that specific differences between individual states could be discerned. These analyses indicated the following pattern of state differences for severe substance abuse/dependency disorder: Wisconsin = Colorado, Colorado = Alabama, Alabama = New Jersey = Florida, and Florida = Mississippi. A similar but slightly different pattern was found at the mild/moderate severity level: Colorado = Wisconsin = Alabama, Alabama = New Jersey = Florida, and Mississippi. Subsequently, in the logistic regression analyses to make states a comparable dichotomous variable as the other independent variables entered into the analyses, the three states with the highest J.Am.Acad. Child Adolesc. Psychiatry, 30:4, July 1991

SUBSTANCE ABUSE PREVALENCE

1. Unadjusted Odds Ratios of Factors Associated with Level 1 (Mild) and Level 2 (Severe) Marijuana or Alcohol Disorder

TABLE

Factor

% SA

Conduct disorder States Depression Placement (MHISCH) Age (15-18/12-14) Gender (F/M) Attention deficit Anxiety Schizophrenia" Conduct disorder Placement (MH/SCH) Depression States Age (15-18/12-14) Gender (F/M) Attention deficit Schizophrenia Anxiety Note: N % SA -

+ versus % SA Level 2 (Severe) 36.1 9.3 24.0 10.0 48.3 17.4 25.0 11.8 24.8 13.1 27.5 15.6 50.0 18.2 25.9 17.4

Level I (Mild/Moderate) 28.1 4.7 29.6 13.3 37.2 17.7 27.8 12.0 28.7 15.6 31.0 18.5 32.8 20.3 36.4 21.1 23.7 20.5

X'

OR

57.34*** 16.49*** 15.72*** 14.86*** 11.45*** 9.06*** 3.37* 2.78*

5.54 2.82 4.56 2.49 2.18 2.06 4.50 1.66

33.64*** 21.23*** 18.75*** 15.04*** 13.21*** 8.88*** 4.50** 2.05 0.62

7.94 2.74 2.74 2.84 2.18 1.98 8.04 2.13 1.21

= 547; % SA + = percentage substance abuse with factor; = percentage substance abuse without factor; OR = un-

adjusted odds ratio; MH = mental health; SCH = special education; F = female; M = male. Within each analysis, psychiatric disorders were at the same severity level as substance-use disorders. "No cases of severe schizophrenia were diagnosed. *p < 0.10; **p < 0.05; ***p < 0.01.

rates (Le., Colorado/Wisconsin/Alabama) were grouped and compared with the three states with the lowest rates (New Jersey/Florida/Mississippi) . Results from the logistic regressions are reported for both mild/moderate and severe levels of substance-use disorder. At the severe level, there were not sufficient numbers of diagnosed cases of schizophrenia (N = 0) and attention deficit disorder (N = 8) to enter these disorders as independent variables in logistic regression. Table 2 lists the significant effects (p < 0.05), ORs, and corresponding 0.95 confidence intervals for severe and mild/moderate levels of substance-use disorders. There was a significant main effect for age (p < 0.05) with those 15 to 18 years of age having higher rates of substance-use disorders than those 12 to 14 years of age, 24.8% versus 13.1% at the severe level, respectively, 1.29 OR, p < 0.05. Figure 2 shows graphically the increased prevalence for the severe level by yearly age categories from ages 12 to 17 (i.e., the 17 age category was composed predominately of respondents who were 17 years of age (N = 53) combined with a few respondents who were 18 years of age (N = 6). The highest age-related prevalence (Le., 34.0%) occurred among those aged 16. There were additional main effects for type of placement and states. Subjects in mental health residential facilities had higher prevalenc'e of severe substance abuse/dependency, 25.0% among adolescents in residential mental health versus 11.8% among those in special education, 2.37 OR, p < 0.001. Additionally, higher prevalence was found among l.Am.Acad. Child Adolesc. Psychiatry, 30:4.luly 1991

study sites located in Wisconsin, Colorado, and Alabama compared with New Jersey, Florida, and Mississippi, 23.96% versus 10.04%, respectively, 1.43 OR, p < 0.02. With regard to comorbidity, both conduct disorder and depression diagnoses were associated with increased rates of substance-use disorders. Among youth with severe conduct disorder diagnoses, 36.1 % were diagnosed with severe substance abuse/dependency versus 9.3% among those who were not conduct disordered, 2.18 OR, p < 0.0001. Similarly, those with a severe depression disorder were more likely to be diagnosed with severe substance abuse/dependency; 48.3% versus 17.0% among those without severe depression, 1.75 OR, p < 0.05. A significant facility x depression interaction, 1.91 OR, p < 0.01, indicated that youth in mental health facilities with depression diagnoses had higher prevalence rates for substance abuse/dependency than those without a depression diagnosis, 80.0% versus 21.9%, respectively. Among those enrolled in special education programs, substance abuse/dependency prevalence was only slightly higher for those with depression diagnoses, 14.3% versus 11.6%, respectively. U, the maximum likelihood measure of goodness of fit for the final regression model of severe substance-use disorders that included all of the above terms was nonsignificant, U (22) = 13.56, p = 0.92, indicating a reasonably good fit of the predicted model to the observed data. Results from analysis of the mild/moderate level of substance abuse diagnosis, which included schizophrenia and attention deficit disorder as independent factors, were virtually identical to those found at the severe abuse/dependency diagnostic level, except that in this model, an additional interaction term, conduct disorder x depression, was significant, p < 0.05, 1.58 OR. This interaction indicated that subjects who had either conduct disorder or depression diagnosis had higher prevalence rates than those with neither diagnosis, 24.7% and 26.7% versus 2.2%, respectively. Subjects with both diagnoses, however, had higher prevalence rates (i.e., 38.8%) than those with only a single disorder, whether the diagnosis was conduct disorder or depression. Table 2 displays significant effects found at the mild! moderate level. Goodness of fit for this final model was adequate, U (24) = 21.39, p = 0.62.

Discussion Results indicate that substance-use disorders among youngsters with serious emotional disturbances occur with relatively high prevalence. This conclusion is supported both by absolute magnitudes of prevalence rate estimates and the relative rank orderings of the various DSM-llI disorders within the sample. At the severe level, the combined substance abuse/dependency disorder is the second most prevalent DSM-III disorder, being exceeded only by conduct disorder. Currently, no directly comparable studies exist on similar prevalence rates for adolescents among either the general population or a clinical group. Some additional support for this conclusion, however, derives from a study of point prevalence that sampled adolescents in the general population. Among a community sample of 150 adolescents aged 14 to 16, Kashani and his colleagues (1987) found that

579

GREENBAUM ET AL.

% WITH SEVERE SUBSTANCE DISORDER

40 35 30 25 20 15 10

5 O'---_-L..... 12 FIG.

---I..-

13

.L.....-

14 15 AGE (YEARS)

----.l

16

--L_ _

17+

2. Prevalence of severe alcohol or marijuana abuse/dependency disorders as a function of age (N = 547).

DSM-III alcohol and drug-related disorders ranked as the sixth and seventh most frequent DSM-III disorders, with point prevalence rates of 5.3% and 3.3%, respectively. Within the current sample, comparable DSM-III alcohol and marijuana disorders of youth aged 14 to 16 ranked fourth and second in frequency among DSM-III diagnoses, with 12 month prevalence rates of 14.1% and 18.0%, respectively. Direct comparisons of prevalence rates between Kashani et al.'s study and the present study are not appropriate, given differences in prevalence metrics. Nevertheless, comparing the relative rank orderings of the various disorders within studies is appropriate. Findings from both studies, along with those of Elliot et al. (1989), suggest an increased role of substance use in the pathological profile of adolescents with serious emotional disorders, compared with substance abuse frequency among a more general community sample. This study finds clear patterns of substance-use disorder comorbidity, patterns that have several features. First, relatively few adolescents with serious emotional disturbances have substance-use problems in isolation from other DSMIII psychiatric disorders. At the mild level, 0.8% of those with substance abuse disorder have no other psychiatric diagnosis versus 22.4% of those without a substance abuse 580

-----IL-

disorder who have no other psychiatric disorder, X2 (1, = 547) = 29.75, P < 0.001,34.12 OR. At the severe level, 22.6% of those with a substance-use disorder have no other psychiatric diagnosis versus 61.8% of those without a substance-use disorder who have no other psychiatric disorder, X2 (1, N = 547) = 51.54, P < 0.001, 25.73 OR. Second, comorbid patterns of substance-use disorder are not equally likely among all core psychiatric disorders. Significant cooccurrence is associated only with conduct disorder and depression. Attention deficit disorders also tend to be associated with substance-use disorders but do not represent unique variance. No association is found for anxiety. Similarly, schizophrenia possibly because of its relatively infrequent occurrence in the sample, is not related to substance disorders. The above findings are congruent with those from DiMilio's aforementioned study of youth undergoing treatment. DiMilio (1989) found that among 57 adolescents, ages 14 to 18, consecutively admitted to inpatient treatment centers for substance abuse and other concurrent psychiatric disorders, conduct disorder was the most frequent cooccurring DSM-III disorder (42%). Depression (35%) was the next most frequent cooccurring Axis I disorder, followed by attention deficit, hyperactivity, or impulse disorder (21 %).

N

l.Am.Acad. Child Adolesc.Psychiatry, 30:4, July 1991

SUBSTANCE ABUSE PREVALENCE

2. Adjusted Odds Ratios of Factors Associated with Levell (Mild) and Level 2 (Severe) Marijuana or Alcohol Disorder

TABLE

Factor

Odds Ratio

Level 2 (Severe) Placement (MH/SCH) 2.37 Conduct disorder 2.18 Depression I. 75 States 1.43 Age (15-18112-14) 1.29 Placement x depression 1.91 Level I (Mild/Moderate) Conduct disorder 2.17 Depression 2.09 Placement (MH/SCH) 1.63 States 1.41 Age 1.28 . Conduct disorder x depression 1.58 Placement x depression 1.32 =

Note: All terms significant atp special education.

0.95 Confidence Interval 1.39-4.02 1.71-2.79 1.03-2.97 1.08-1.90 1.01-1.65 1.12-3.25 1.39-3.37 1.33-3.26 1.26-2.11 1.09-1.83 1.02-1.61 1.01-2.46 1.03-1.71

< 0.05; MH = mental health; SCH

Rates of schizophreniform and anxiety disorders were low (Le., 7%). Previous studies have also found elevated rates of substance use among depressive (Deykin et al., 1987; Famularo et al., 1985) and conduct disordered youth (Elliot et al., 1989; Robins, 1978). The strong relationship between residential mental health placement and substance abuse needs further clarification. Possibly both factors reflect increased severity of illness rather than a direct association between substance use and residential placement. Greater frequencies of multiple diagnoses among those in residential placement may reflect the tendency for those with increased severity of disturbance being more likely to enter the mental health system (i.e., Berkson's bias). Presumably, those who are less disturbed remain community-based and in public schools, while more severe youth are placed in residential facilities. Alternatively, involvement with substances may function as a highly specific marker that state and local agencies use to decide entry into residential placement. Under these conditions, aside from differential substance use, youngsters in both systems may have similar severity of disturbances. Future research should examine the role of substance use in the paths of entry into the two systems of care examined in this study. A marked age effect also was found in the current study. Among a community sample of adolescents (Elliot et al., 1989), substance use has been found to follow a maturational reform hypothesis, increasing from adolescence to young adulthood (Le., age 20) and then declining. Results of the current study are consistent with both an increase with age, up to 16 years, and then a decline among 17- to 18-year olds. Additional future research, already underway as part of the continuing NACTS study, will examine the persistence of substance-use involvement among these adolescents. Such prospective longitudinal data could clarify whether, among SED youth, substance-use disorders follow the maturational reform hypothesis and decline with age J.Am.Acad. Child Adolesc.Psychiatry, 30:4, July 1991

during the transition to adulthood; or conversely, continues to follow the upward trend that is observed from ages 8 to 16 years among the cross-sectional data of this study. Significant differences in prevalence rates between states were also found. Such differences possibly reflect state differences in definition and identification of SED adolescents in association with differential availability of substances to underage youth. The lack of any significant interaction of state prevalence rates with any other independent factor, particularly other psychopathologies, further suggests that state prevalence differences, whether arising from administrative or historical causes, do not moderate patterns of significant comorbidity found in the data. Thus, although states may differ in prevalence rates, the observed comorbidity pattern can be generalized across these state differences. As DSM-III diagnostic criteria used in this study have been supplanted by DSM-III-R. consideration needs to be given as to how these results would have been affected by contemporary diagnostic criteria. The most substantive changes, at least for the current study, have occurred among criteria for psychoactive substance-use disorders. Within this category of disorders, three important diagnostic changes have occurred. First, dependence disorder criteria have been broadened so that less importance has been given to tolerance or withdrawal symptoms. Such symptoms are no longer necessary to obtain a dependence diagnosis, thus making it easier for heavy substance using adolescents, who have a relatively shorter history of chronic use than adults and typically show fewer tolerance/withdrawal symptoms than adults, to get a dependence diagnosis. In turn, similar easing of diagnostic criteria has occurred for an abuse diagnosis that no longer requires evidence of impairment but only requires evidence that a maladaptive pattern of use exists. Finally, inconsistencies in criteria between substances (i.e., alcohol versus marijuana) for obtaining either an abuse or dependence diagnosis have been eliminated. As noted, changes in DSM-III-R for psychoactive substance abuse disorders involved no new or additional symptoms among diagnostic criteria but constituted only redefinitions among criteria for the various substance-use disorders. Therefore, it was possible to construct algorithms reflecting DSM-III-R criteria for psychoactive substance-use disorders, and these were implemented with the data to assess any changes in prevalence of substance-use disorders among the sample. As expected, based on less restrictive diagnostic criteria (i.e., eliminating tolerance or withdrawal symptoms), more subjects overall met criteria for psychoactive substance dependence. Specifically, the prevalence rate of alcohol dependence decreased from 7.5% to 6.4%, marijuana dependence increased from 11.7% to 18.1%, and those with either alcohol or marijuana dependence increased from 15.0% to 20.1 %. In contrast, abuse diagnoses tended to decline, with no changes in mild alcohol abuse and a decrease in mild marijuana and combined abuse (Le., from 16.1 % to 12.4% and from 19.0% to 16.1 %, respectively). At the severe level, alcohol abuse increased slightly from 5.7% to 6.4%, whereas marijuana and combined alcohol or marijuana abuse declined (i.e., from 10.4% to 2.7% and

581

GREENBAUM ET AL.

from 13.7% to 8.2%, respectively). When grouped by severity level, those having at least mild alcohol or marijuana abuse disorders decreased from 21.8% to 20.3%, while the prevalence rate of severe alcohol or marijuana abuse/ dependence disorders increased from 18.7% to 20. 1%. Therefore, under DSM-III, the current data, by a small degree, tend to understate the severity of substance-use disorders among this population as compared with DSM-III-R criteria. Changes in DSM-III-R also have affected psychiatric disorder diagnoses. A large number of diagnostic criteria, however, remain virtually unchanged, particularly for anxiety, schizophrenia, and depression disorders. Changes that have occurred include shifting of criteria among some of the more narrow psychiatric diagnoses, such as the subtypes of conduct disorder that have been reduced from five to three in the current DSM-III-R or the four types of attention deficit disorder that now have been reduced to a single type. However, these changes again do not affect prevalence rates reported in this study, as only broad categories of disorders (i.e., any conduct disorder diagnosis, any attention deficit disorder, etc.), which have remained virtually unchanged in the DSM-III-R revision, have been reported. Finally, conduct disorder diagnosis, the most prevalent psychiatric disorder in the current sample (i.e., 72.8% at the mild/moderate level and 34.9% at the severe level), has been altered by (1) adding two symptoms that count toward diagnostic criteria and (2) raising the threshold for obtaining a diagnosis. Thus, the criteria for conduct disorder diagnosis have been eased and made more restrictive simultaneously. As it is not possible to know how subjects would have met these new criteria, changes in conduct disorder prevalence rates remain unclear. In summary, DSM-III-R criteria would tend to shift prevalence rates of substance abuse disorders into more severe categories, but these increases would be slight and presumably would not change the basic pattern of results reported in this study. A number of implications for practitioners can be gleaned from the results of this study. First, among adolescents who have conduct or depression disorders, assessing psychoactive substance abuse/dependence is highly recommended. When such assessments indicate dual disorders, the utility of providing combined mental health and substance abuse treatment seems warranted and has been advocated by many (Behar, 1990, unpublished manuscript; Elliot et aI., 1989; Osher and Kofoed, 1989). Perhaps a less obvious implication for treatment is that even without a positive indicator of concurrent substance abuse/dependency, clinicians should be sensitive to the high-risk vulnerability of conduct disordered and depressed adolescents for developing substanceuse disorders. Interventions of a preventive character should be initiated, particularly among children and early adolescents who have yet to reach late adolescence and young adulthood, the typical period of substance abuse onset. Another implication for practitioners includes possible redefinition of diagnostic classifications (e.g., DSM-IV, DSM-V) that consider dual disorders of psychoactive substance use and either conduct disorder or depression as distinct diagnostic subtypes. A number of theorists already 582

have argued for an adolescent disorder based on multiple problems that include acting-out behavior, delinquency, and substance abuse (Donovan et aI., 1988; Donovan and lessor, 1985; lessor and lessor, 1977). Comorbidity patterns found in this study support such a diagnostic entity. However, before such elevated frequencies attain causal status, etiologies different from those with only one disorder would need to be established. Currently, the cause of these disorders is unknown. Among the dually diagnosed, controversy exists as to whether substance abuse is a symptom of an underlying mental health problem or conversely, whether the mental health problem is symptomatic of alcohol or drug use. Depending on the practitioner's answer to this question, often the type of treatment will vary, with the primary focus of treatment being control of either drug use or antisocial behavior. Within the current sample, a strong age effect for the onset of substance abuse is consistent with the idea that the behavioral or emotional problem preceded the substance abuse; thus, the root cause may be construed as a mental health problem. However, these conclusions are speculative and demand strong caveats as they are (1) based on cross-sectional rather than prospective longitudinal data, (2) correlational rather than experimental in nature, and (3) derived from a sample identified as having mental health rather than substance abuse problems. Moreover, merely using relative age of onset as evidence for causal priority does not preclude the possibility that both mental health and substance abuse conditions have been caused by a third as yet unspecified condition or variable. In summary, results from this study indicate that substance-use disorders are (1) a major component of the clinical profile characterizing a large number of adolescents with serious emotional disturbances and (2) should be addressed concurrently among adolescents who suffer from other serious emotional disorders, particularly conduct disorder and depression. Incorporating this knowledge into future assessment and treatment programs for such youth could lead to more successful outcomes. References Bukstein, O. G., Brent, D. A. & Kaminer, Y. (1989), Comorbidity of substance abuse and other psychiatric disorders in adolescents. Am. J. Psychiatry. 146:1131-1141. Costello, A. J., Edelbrock, C. S., Dulcan, M. K., Kalas, R. & Klaric, S. H. (1984), Development and testing of the NIMH Diagnostic Interview Schedule for Children on a clinical population: final report. (Contract No. RFP-DB-81-0027). Rockville, MD: Center for Epidemiological Studies, National Institute of Mental Health. Deykin, E., Levy, J. C. & Wells, V. (1987), Adolescent depression, alcohol, and drug abuse. Am. J. Public Health, 76:178-182. DiMilio, L. (1989), Psychiatric syndromes in adolescent substance abusers. Am. J. Psychiatry, 146: 1212-1214. Donovan, J. E. & Jessor, R. (1985), Structure of problem behavior in adolescence and young adulthood. J. Consult. Clin. Psychol., 53:890-904. - - - - Costa, F. M. (1988), Syndrome of problem behavior in adolescence: a replication. J. Consult. Clin. Psychol., 56:762-765. Elliot, D. S., Huizinga, D. & Menard, S. (1989), Multiple Problem Youth: Delinquency, Substance Use, and Mental Health Problems. New York: Springer-Verlag. Famularo, R., Stone, K. & Popper, C. (1985), Preadolescent alcohol J.Am.Acad. Child Adolesc.Psychiatry, 30:4, July 1991

SUBSTANCE ABUSE PREVALENCE

abuse and dependence. Am. J. Psychiatry, 140:1187-1189. Gerstley, L J., Altennan, A. I., McLellan, A. T. & Woody, G. E. (1990), Antisocial personality disorder in patients with substance abuse disorders: a problematic diagnosis? Am. J. Psychiatry, 147: 173178. Helzer, J. E. & Pryzbeck, T. R. (1988), The co-occurrence of alcoholism with other psychiatric disorders in the general population and its impact on treatment. J. Stud. Alcohol, 49:219-224. Hesselbrock, M. N., Meyer, R. E. & Keener, J. J. (1985), Psychopathology in hospitalized alcoholics. Arch. Gen. Psychiatry, 42: 10501055. Jessor, R. & Jessor, S. L. (1977), Problem Behavior and Psychosocial Development: A Longitudinal Study of Youth. New York: Academic Press. Kashani, J. H., Beck, N. C., Hoeper, E. W. et al. (1987), Psychiatric disorders in a community sample of adolescents. Am. J. Psychiatry, 144:584-589. Lehman, A. F., Myers, C. P. & Corty, E. (1989), Assessment and classification of patients with psychiatric and substance abuse syndromes. Hosp. Community Psychiatry, 40:1019-1024.

J.Am.Acad. Child Adolesc. Psychiatry, 30:4, July 1991

Lett, P. (1988), Dual diagnosis: psychiatric disorder & substance abuse.

Journal of Applied Rehabilitation Counseling, 19:16-20. Menicucci, L. D., Wermuth, L. & Sorensen, J. (1988), Treatment providers' assessment of dual-prognosis patients: diagnosis, treatment referral, and family involvement. Int. J. Addict., 23:617-622. Osher, F. (1989), The dually diagnosed: patient characteristics and treatment strategies. Community Support Network News, pp. I, lO-

ll. - - Kofoed, L. L. (1989), Treatment of patients with psychiatric and psychoactive substance abuse disorders. Hosp. Community Psychiatry, 40: 1025-1030. Robins, L. N. (1978), Sturdy childhood predictors of adult antisocial behaviour: replications from longitudinal studies. Psychol. Med., 8:611-622. Ross, H. E., Glaser, F. B. & Germanson, T. (1988), The prevalence of psychiatric disorders in patients with alcohol and other drug problems. Arch. Gen. Psychiatry, 45:1023-1031. ' Schuckit, M. A. (1983), Alcoholism and other psychiatric disorders. Hosp. Community Psychiatry, 34: 1022-1027.

583