Psychopathy trait scores in adolescents with childhood ADHD: the contribution of genotypes affecting MAOA, 5HTT and COMT activity

Objectives Psychopathy-related traits, especially those tapping the 'emotional dysfunction' aspect of psychopathy that is characterized by lack of emotional responsiveness, are thought to be of genetic origin, but molecular genetic studies are yet to be undertaken. Gene variants that affect COMT, MAOA and 5HTT activity have previously been linked to antisocial behaviour. The aims of this study were to test whether these gene variants are linked to psychopathy traits in attention-deficit hyperactivity disorder (ADHD). Methods Adolescents were followed up 5 years after an initial diagnosis of ADHD. Psychopathy trait scores were assessed [total scores and 'emotional dysfunction' (also referred to as 'affective') scores] and the MAOA 30-bp variable number of tandem repeats, SLC6A4 44-bp insertion/deletion and COMT Val1 58Met variants were genotyped. Results All three gene variants were associated with 'emotional dysfunction' scores. MAOA and 5HTT variants were associated with total psychopathy scores. The results were not explained by associated conduct disorder. Conclusion The results suggest that specific gene variants influence psychopathy traits in ADHD. Psychiatr Genet 19:312-319 (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.