The association between childhood irritability and liability to substance use in early adolescence: a 2-year follow-up study of boys at risk for substance abuse.

The aim of this investigation was to determine whether irritability, defined as the propensity to experience and express anger following actual or perceived provocation, is a component of the liability to alcohol and drug abuse. Sons of substance abusing fathers (n = 40) and normal fathers (n = 56) were studied when they were 10-12 years of age and followed-up 2 years later. Hierarchical regression analysis revealed that resting salivary cortisol concentration, impulsivity and family discord measured when the subjects were 10-12 years of age explained 35% of the variance on a scale measuring irritability 2 years later. At follow-up, when the boys were 12-14 years of age, it was observed that irritability scale scores and family discord were the only variables that accounted for significance variance on a scale measuring coping via alcohol and drug use. Latency and amplitude of the N1 and P3 event-related potentials of an auditory oddball task, measured at age 10-12, were not associated with drug use at age 12-14. These results indicate that family dysfunction, stress state of the child, and low behavioral self-control additively account for a significant proportion of variance on irritability scale scores 2 years later, and that this trait, in conjunction with family discord, is associated with substance use as a coping response by early adolescence.