This paper reports the neurological findings in 286 patients with a history of recurrent attacks of uncontrollable rage occurring with little or no provocation and dating from early childhood or from a physical brain insult at a later date. Objective evidence of developmental or acquired brain defects was found in 94 per cent. The most common abnormality was minimal brain dysfunction, which was present in 41 per cent. The diagnosis was not made on behavioral symptoms alone; there had to be positive neurological and/or laboratory evidence (electroencephalogram, computerized axial tomography scan, x-rays, psychological tests). The most common symptom apart form episodic dyscontrol was complex partial seizures which had occurred at some time in the life of 30 per cent of the patients. In many the seizures had not been recognized as epileptic because of their subtle form and rare occurrence. Convulsions and dramatic attacks with unconsciousness were rare. One third of the patients presented a variety of psychiatric disorders persisting for days, weeks, or months in addition to episodic rage. Another type of periodicity was exhibited by women whose episodes occurred solely or mainly in the premenstrual week. Detection of both adult minimal brain dysfunction and complex partial seizures requires detailed and well informed interrogation because many of the symptoms are far from obvious and are unlikely to be uncovered by a superficial medical history or neurological examination.