Abstract

Study 1.

Aim. To review the published literature that could provide information on the development, extent, and predictors of psychiatric comorbidity with substance use and abuse in children and adolescents. Method. From a review of 141 published papers, 21 were identified that could contribute to a meta-analysis of the extent of comorbidity with three disruptive behavior disorders (DBDs): conduct disorder (CD), oppositional defiant disorder (ODD), and attention deficit hyperactivity disorder (ADHD), and with depression and anxiety. Results. Comorbidity was highest with the DBDs and lowest with anxiety. Controlling for comorbidity among psychiatric disorders reduced the odds ratios but maintained their relative ranking. Odds ratios for comorbidity with substance abuse/dependence were higher than those for any use. The excess risk associated with abuse/dependence compared with any use was highest for ADHD and depression, lowest for CD. Sex was the only correlate available for meta-analytic review of causes and correlates. For both abuse/dependence and any use, the odds ratios for comorbidity were higher in girls than boys, significantly so for CD and anxiety. Conclusions. While psychiatric comorbidity with drug abuse is high, varying by diagnosis, published data are lacking on correlates, risk factors, temporal ordering, and treatment.

Study 2.

Aim. To review the information available in existing data sets that could contribute to a more detailed examination of correlates and risk factors of psychiatric comorbidity with substance use and abuse, and of the temporal relationships between psychiatric disorders and drug abuse. Methods. We identified 65 potentially useful data sets, and sent out a questionnaire to the Principal Investigators. Results. Sixteen data sets met the minimal requirements of representative sampling, psychiatric diagnoses, data on drug abuse, and information on timing. Most were panel studies with repeated assessments of participants. Data are available on over 17,000 youth, providing some 84,000 person-observations over time. Of these, 50 percent are female, about 3,500 (11,000 person-observations) are African American, 2,700 (6,000 person-observations) are Hispanic, and 450 (2,000 person-observations) are American Indian. The age ranges of the studies cover the period from birth through age 26. Conclusions. Given modern methods of data analysis, and the impressive resource represented by the data sets available, there is a real opportunity to advance understanding of the predictors and timing of psychiatric comorbidity with drug abuse, using existing data.

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Introduction

In this report we present an overview of the data available to estimate the co-occurrence of psychiatric disorders with drug use, abuse, and dependence in childhood and adolescence. We provide this as background to the discussion of the impact of childhood interventions on subsequent drug use.

In order for childhood interventions to have an effect on subsequent drug abuse, they need to affect risk factors for later drug use. In these analyses we concentrate on psychiatric disorders of childhood and adolescence as potential risk factors for later drug abuse. The policy question is where it makes most sense to target early interventions. For example, if depression and drug abuse co-occur in childhood, an intervention program could have an effect on future drug abuse by reducing current drug use, or by ameliorating current depression, or both. A program targeting only childhood drug use might have little effect on children put at risk for future drug abuse primarily by their history of depression, while a program targeting only childhood depression might have little effect on youth put at risk by early drug use. If childhood depression and drug use co-occur, it would be helpful for program planners to know how often, whether the risk is the same across the population, or is higher in some groups, and how depression affects the risk of later drug abuse as children move into adolescence and early adulthood. The same is true of other psychiatric disorders of childhood.

The first question, then, is how often drug use and abuse co-occur with psychiatric disorders. Second, one would like to know whether co-occurrence is more common with some disorders than with others, and conversely, whether some forms of drug abuse are more likely than others to be comorbid with specific psychiatric disorders. Third, are some groups of children (boys or girls, younger or older children, White or minority groups, poor or nonpoor, urban or rural) more at risk than others of co-occurring psychiatric disorders and drug abuse? Fourth, understanding the temporal sequencing of psychiatric disorders and drug abuse would help in planning interventions. In particular, it would be helpful to know how a disorder that co-occurs with drug abuse in childhood or adolescence affects later risk of drug abuse. With this information available, it might be possible to estimate the attributable risk, or the proportion of later drug abuse that would be prevented by intervening with one risk factor (e.g., early depression) rather than another (e.g., early drug use). This kind of calculation is often useful to policy planners making cost-/efficiency-based choices among programs.

In this report we review the data relevant to the first and second questions: the co-occurrence of specific psychiatric disorders with drug use and abuse/dependence in children and adolescents. We present a meta-analysis of comorbidity with five different groups of psychiatric disorders based on the published literature. Questions 3 and 4 cannot yet be answered from the published literature, but in the second part of this report we provide an overview of existing data sets that have the potential to provide answers to some of these questions.

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