We investigated possible causative factors for the high epileptic suicide rate by reviewing the cases of 22 patients with idiopathic epilepsy found among 711 patients hospitalized for a suicide attempt by overdose. Suicide attempts occurred with increased seizure activity in one epileptic; otherwise, no relationships were found with seizure-related variables. When matched by age, sex, and race with 44 nonepileptic controls from the same population, the epileptics had more borderline personality disorders with multiple impulsive suicide attempts (45.5% vs 13.6%), more psychotic disturbances, including command hallucinations (31.8% vs 9.1%), fewer adjustment disorders (18.2% vs 45.5%), and a comparable frequency of depression (13.6% vs 25%). We conclude that suicide attempts in epileptics are primarily associated with interictal psychopathologic factors, such as borderline personality disorder and psychosis, rather than with specific psychosocial stressors, seizure variables, or anticonvulsant medications.