Main and interaction effects of childhood trauma and the MAOA uVNTR polymorphism on psychopathy.

Psychopathy is characterized by callous affect, interpersonal manipulation, a deviant lifestyle, and antisocial behavior. Previous research has linked psychopathic traits to childhood trauma, but also to the upstream variable number tandem repeat (uVNTR) polymorphism of the monoamine oxidase A (MAOA) gene. An interaction between childhood trauma and MAOA genotype has been associated with antisocial behavior, but so far little is known about interaction effects of childhood trauma and the MAOA uVNTR on psychopathy. In order to bridge this gap, we used data of 1531 male and 1265 female twins and their siblings from a Finnish community sample to estimate structural equation models. The psychopathy and childhood trauma constructs were conceptualized as bifactor models with one general and two orthogonal group factors. Data comprised self-reports on childhood trauma and psychopathic traits as well as MAOA uVNTR genotype. In both genders, childhood trauma was associated with the general factor that represents the overarching psychopathy construct, and with the group factor that captures social deviance, but not with the group factor capturing psychopathic core personality traits. Women with a low activity variant of the MAOA uVNTR reported slightly higher levels of psychopathy than those with a high activity allele, but only with respect to the general psychopathy factor. There was no evidence for an interaction effect between MAOA uVNTR genotype and childhood trauma on psychopathy in either gender. Our results suggest that psychopathy in general and social deviance in particular are associated with childhood trauma in men and women, and that psychopathic traits are subject to variation in the MAOA uVNTR genotype in women.