Combination of Conduct Disorder and ADHD Predictive of Substance Abuse

Caroline Helwick

June 01, 2010

June 1, 2010 (New Orleans, Louisiana) — In a 10-year follow-up study of children with attention-deficit/hyperactivity disorder (ADHD), the occurrence of substance use disorder (SUD) was increased compared with controls, especially among ADHD youth with early conduct disorder, according to a study from Massachusetts General Hospital and Harvard Medical School, Boston.

The study was presented here at the American Psychiatric Association (APA) 2010 Annual Meeting.

ADHD and associated comorbidity are known to be risk factors for substance abuse in adolescence and young adulthood, but few studies have examined the early childhood risk factors that may predispose patients to this behavior, said Timothy E. Wilens, MD, and colleagues from the Pediatric Psychopharmacology Unit at Massachusetts General Hospital.

"We hypothesized that early delinquency and academic or cognitive dysfunction will predict later SUD in 2 cohorts of ADHD children, followed for an average of 10 years. We examined early predictors for later SUD," Dr. Wilens said.

As part of 2 identically designed longitudinal, case-control, family studies of youth with ADHD, the study compared 257 youth with ADHD to 225 without ADHD, aged 6 to 17 years at baseline.

Subjects were followed up for approximately 10 years. All youth were assessed in a masked manner using Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) Schedule for Affective Disorders and Schizophrenia for School-Aged Children epidemiologic edition or Structured Clinical Interview for DSM Disorders, cognitive measures, Family and Environmental Scale, and Social Adjustment Inventory for Children and Adolescents rating scales. Psychopathology and SUD were determined by structured interview.

At baseline, the subjects' mean age was 11 years and 50% were male. Most were whites from middle-class families. The subjects and controls were similar except that ADHD subjects were significantly more likely to have a parental history of alcohol use disorders (P < .001) and drug use disorders (P = .003).

Investigators found that children with ADHD were 1.5 times more likely to develop an SUD compared with controls. Within ADHD, comorbid oppositional defiant disorder and conduct disorder were significant predictors of any SUD, after adjusting for sex (hazard ratio, 2.31; P < .001) and parental history of SUD (hazard ratio, 3.0; P < .001), Dr. Wilens and colleagues reported.

Within the population of ADHD youth who developed drug use disorders, comorbid major depressive disorder was a further significant predictor, essentially doubling the risk (P = .006). Interestingly, boys who received extra help in school were approximately half as likely to develop an SUD (P = .02), the analysis showed.

"In general, gender did not predict risk for SUD, and we found no significant associations between baseline cognitive or academic dysfunction and later SUD in our ADHD youth," Dr. Wilens said. "No significant results were found for social or family environment factors, cognitive factors, or any school functioning factors."

R. Scott Benson, MD, a child and adolescent psychiatrist in Pensacola, Florida, and a member of the APA Council on Communications, commented on the findings for Medscape Psychiatry.

"Dr. Wilens and colleagues showed that there are children with ADHD that are at risk for substance abuse but most of them have a diagnosis of conduct disorder, which translates into juvenile delinquency later. Many ADHD children want to be good. For the child with conduct disorder, being good is not a priority. This work says that ADHD plus conduct disorder equals a very serious problem," Dr. Benson said.

"Dr. Wilens answers convincingly that the vast majority of ADHD children will not abuse drugs later, but if the child has more severe, more oppositional, behaviors we have to acknowledge that he may be heading for a life of trouble," he continued.

"This is the challenge for psychiatrists, to find ways to treat the comorbidities. This requires enormous resources and follow-through to prevent these children from being school dropouts and ending up in juvenile court."

Dr. Wilens reported receiving consulting fees, speakers' fees, or grant support from Abbott, AstraZeneca, McNeil, Eli Lilly, Novartis, Merck, and Shire. Dr. Benson has disclose no relevant financial relationships.

American Psychiatric Association (APA) 2010 Annual Meeting: Abstract NR5-22. Presented May 25, 2010.


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