The expediency of distinguishing three periods of craniocerebral trauma--initial, early, and late with two subperiods--is substantiated by the results of psychiatric studies. The terms used reflect a common criterion--the lapse of time between the period and the moment of the trauma. The changes in and the supplements to the periodization accepted in the fifties were suggested by the results of examination of patients with cerebral trauma of such severity which was considered then incompatible with life but is marked today by prolonged coma and extremely protracted (up to 12 months and more) recovery of consciousness after coma. For such patients (a) each period (the initial one in particular) lasts longer and (b) syndromes occurring in each period are attended by new conditions which were not encountered in the fifties--the apallic syndrome or vegetative status, akinetic mutism, and other conditions.