Background Impulsive aggression in adulthood is associated with disturbances in serotonergic function. In contrast, research examining this association in childhood has yielded inconsistent results.

Aims The current study examined the prospective relationship between serotonergic function measured in childhood and the later emergence of antisocial personality disorder.

Method Hormonal response to fenfluramine, an index of serotonergic function, was assessed in 58 children with attention-deficit hyperactivity disorder between 1990 and 1997 when they were aged 7-11 years. Approximately 9 years later these individuals were evaluated for antisocial personality disorder.

Results Lower serotonergic responsivity assessed in childhood predicted the development of antisocial personality disorder (t (56)=2.25, P=0.028).

Conclusions These results provide a critical link between the child and adult literature on the covariation of impulsive aggression and serotonergic function and suggest a potential explanation for inconsistencies in the childhood literature.