ADHD, stimulant treatment in childhood and subsequent substance abuse in adulthood — A naturalistic long-term follow-up study

• This is the longest and most complete follow-up study of children with ADHD.
• 208 children with ADHD were followed until a mean age of 31 years.
• Childhood ADHD increased the risk for SUD in adulthood.
• Both girls and boys with ADHD were at increased risk.
• Early initiation of stimulant treatment in childhood reduced the risk of later SUD.

The purpose of the study was to estimate the risk of substance use disorder (SUD) and alcohol abuse in adulthood among children and adolescents with attention-deficit hyperactivity disorder (ADHD) compared to the background population. Furthermore, to examine whether the age at initiation and duration of stimulant treatment in childhood predicts SUD and alcohol abuse in adulthood. 208 youths with ADHD (183 boys; 25 girls) were followed prospectively. Diagnoses of SUD and alcohol abuse were obtained from The Danish Psychiatric Central Register. The relative risk (RR) of SUD and alcohol abuse for cases with ADHD, compared to the background population was 7.7 (4.3–13.9) and 5.2 (2.9–9.4), respectively. Female gender, conduct disorder in childhood and older age at initiation of stimulant treatment increased the risk of later SUD and alcohol abuse. Our results warrant increased focus on the possibly increased risk of substance abuse in females with ADHD compared to males with ADHD.