The risk of early drug use asociated with ADHD was evaluated in a community-based sample of 717 (412 low birth weight, 305 normal birth weight) children examined at 6 years of age and at follow-up at age 11 years, at the Department of Psychiatry, Henry Ford Health Sciences Center, Detroit, MI. Of 137 (19%) who had used drugs at least once, 10.6% had used tobacco, 10.1% alcohol, 3.8% inhalants, and only 7 children had used marijuana. Independent of low or normal birth weight, ADHD at age 6 years increased the odds of drug use to 1.7 compared to 1 in non-ADHD children; the incidence of drug use by 11 years of age was 29% in ADHD compared to 16% in non-ADHD children. The higher the number of ADHD symptoms, the higher the risk of drug use. The higher the incidence of externalizing behavior problems associated with ADHD, the greater the risk of drug use; the odds of drug initiation in children with ADHD versus without ADHD was 2.09 (35% vs 20.1%). Internalizing problems at age 6 showed no association with drug use by age 11. Low levels of parent monitoring and high drug use by peers increased the risk of drug use, independent of the ADHD. Treatment of ADHD with methylphenidate (MPH) was unrelated to the risk of drug use; the incidence of drug use was 31% in those treated and 28% in children not receiving MPH (20% of children with ADHD were on stimulant therapy at 11 years of age). 
COMMENT. Children with ADHD at 6 years of age have an increased risk of drug use by age 11 years. Externalizing behavior problems, inadequate parent monitoring, and drug use by peers increase the risk of drug use. Early treatment of behavior and conduct disorders often associated with ADHD, increased parent monitoring, and reduced association with drug-using peers might be effective in reducing the incidence of drug use in children with ADHD.
Effects of stimulant treatment on drug abuse. Stimulant treatment of ADHD neither increases nor decreases the risk of early drug use in the Detroit study, a finding at variance with that of Biederman J, et al , who found that children with ADHD who received stimulants for at least 4 years were at a significantly reduced risk for developing substance abuse disorder than unmedicated children. Contrary to some reports that stimulant medication may encourage later substance abuse in children with ADHD, the report by the Massachusetts General Hospital researchers indicates a protective effect from stimulant therapy.
Drug use in adults with persisting ADHD. Childhood onset ADHD, persisting in adults without psychiatric comorbidity, carried a 52% lifetime risk of drug (mainly marijuana) and drug plus alcohol use compared to 27% of non-ADHD adults. (Biederman J et al, 1995; see Progress in Pediatric Neurology III, PNB Publ, 1997;pp232-233). Psychiatric comorbidy increases the risk of drug abuse in adults.
Psychiatric comorbidity with ADHD. In a study of 105 child and adolescent twins with, and 95 without, ADHD at the University of Colorado, Boulder, CO, inattentive subtypes were associated with lower IQ and higher levels of depression, whereas hyperactivity-impulsivity was associated more strongly with ODD and CD. Combined types were associated with more disruptive behavior than the other 2 subtypes. 
MPH and Adderal compared in school-age ADHD children. Both stimulants improved teacher and parent behavior ratings. A single dose of Adderal was as effective as two daily doses of MPH. Sadness was the most frequent side effect common to both drugs, occurring in 10-12% at optimal dose levels . Adderal may be preferred to MPH in older children, who often object to school involvement in lunch time doses. (see Ped Neur Briefs June 1999; 13:44, for previous comparison study of Ritalin and Adderal in ADHD).