In a large number of studies, hostility, impulsivity and aggression have been demonstrated to be associated with decreased activity of the serotonergic system (Nelson and Chiavegatto 2001). In rodents a specific role for the serotonin-1b receptor has been reported (Olivier et al. 1995) and it has been shown that specific central serotonin-1b/d agonists such as lipophilic triptans have a specific anti-aggressive effect. To date, no studies have been conducted on treatment of hostility, impulsivity or aggression among humans using a triptan.