Cohesiveness, an essential element in successful therapy groups, is difficult to establish and maintain in inpatient settings where group membership is constantly changing. Cohesiveness can be increased by the use of a closed group model, in which all members begin the group on a specified day and remain in the group for a predetermined number ofsessions. Such groups must work through four developmental phases. The first phase, in which group members overidentify with the problems of other members, is followed by a phase characterized by disenchantment with the group. In the third phase members seek to achieve both indepen- dence and intimacy simultaneously, and the final phase involves separation from the group. According to the author, the primary disadvantage of closed ther- apy groups is that they can be used only in certain settings.