Association of aggressive behavior with altered serotonergic function in patients who are not suicidal

Objective: The purpose of this study was to determine whether aggression an d serotonergic dysfunction are related in the absence of a history of suici dal behavior. Although serotonergic dysfunction has been implicated in aggr essive and impulsive behavior, most studies of such behavior have included individuals with a history of suicide attempts. Low concentrations of CSF 5 -hydroxyindoleacetic acid (5-HIAA) have been consistently associated with s uicidal behavior, presenting a potential confound in the link between aggre ssion and serotonergic dysfunction. Method: The authors examined the associ ation between aggression and CSF 5-HIAA concentrations in a group of 64 pat ients who had different DSM-III-R axis I diagnoses and no past suicidal beh avior. Aggressive (N=35) and nonaggressive (N=29) groups were defined by a median split on a six-item history of adulthood aggressive behavior. Result s: The aggressive group had significantly lower CSF 5-HIAA concentrations t han the nonaggressive group. Aggressive individuals also scored significant ly higher on self-report measures of hostility, impulsiveness, and sensatio n seeking. CSF 5-HIAA concentrations, however, did not correlate with self- reported hostility and impulsivity. Conclusions: There is an association be tween aggressive behavior and serotonergic dysfunction independent of suici dal behavior in patients with axis I disorders who exhibit relatively milde r forms of aggressive behavior. Analogous to findings with suicidal behavio r, a low concentration of CSF 5-HIAA is related to aggressive behavior but does not show the same relationship to the continuum of aggressive feelings and thoughts.