Attention Deficit Disorder is a well recognized developmental disorder in children. The disorder has been found to persist in adulthood in about 50% of the cases with an estimated adult prevalence of about 3.5%. ADD in adulthood is characterized by high rates of one or more concurrent psychiatric disorders like mood disorders, anxiety disorders and personality disorders.

In the last decade interest has increased in the co-occurrence of ADD and substance use disorders (SUD). Approximately 15-25 % of ADD patients have a lifetime diagnosis of SUD involving a wide range of legal and illegal substances. Given the different spectrum of ADD symptomatology as compared to the childhood clinical picture, the high rates of psychiatric co-morbidity and the interference of substances with ADD symptoms and course, diagnosis and treatment of these patients constitute a real challenge.

Recent clinical research is directed at unravelling specific risk factors for developing SUD during the course of ADD in later life. Early diagnosis and adequate treatment seem to diminish this risk. Childhood conduct disorder and increased impulsivity are considered to imply an increased risk for developing not only SUD but also criminality in (early) adulthood. Clinical implications of these findings will be discussed during this presentation.