Attention-deficit hyperactivity disorder (ADHD) symptoms include inattention, motor hyperactivity and impulsiveness. Roughly half of the adults who report ADHD symptoms also report a co-existing substance-abuse disorder. New findings published in the October issue of Alcoholism: Clinical & Experimental Research have identified a distinct phenotype or "profile" of individuals with co-existing ADHD and alcoholism. Although prior studies have suggested a genetic commonality of ADHD and alcoholism, the study found no significant contribution of two specific candidate genes, the promoter polymorphism of the serotonin transporter gene (5-HTT) and the 5-HT2c receptor Cys23Ser polymorphism.
"Our results indicate that individuals with persisting ADHD symptoms in adulthood seem to be at high risk of developing an alcohol-use disorder," said Monika Johann, medical doctor and research associate at the University of Regensburg and first author of the study. "Moreover, there is evidence for a highly increased severity of alcohol dependence in subjects with ADHD."
Researchers examined 314 adult alcoholics (262 males, 52 females) as well as 220 unrelated healthy control subjects, all of German descent. Each participant was assessed for psychiatric disorders, such as substance-use disorders (including alcoholism), ADHD, and antisocial personality disorder (APD). Patients with a history of major psychiatric disorders, including depression a