In our longitudinal study of a large U.K. population sample, ALSPAC, we found that childhood stressful life events and family adversity, in particular maternal psychopathology and social deprivation experienced in the first few years of life, were associated with behavioral disinhibition detectable as early as age four years. The components of overall adversity and the timing had differing effects on behavior and no one component adequately explained all the variation (Tables 2, 3). In girls, the interaction of MAOA-LPR with stressful life events experienced from ages 6 months to 3 ½ years predicted hyperactivity at ages 4 and 7 years. In boys, the interaction of MAOA-LPR with stressful life events experienced between ages 1 ½ and 2 ½ years predicted hyperactivity at 7 years. Although early-life family adversity was a strong predictor of behavioral disinhibition there was no interaction with MAOA-LPR genotype. It may well be that different stressors interact with different genes at different time-points during development to influence behavior.
