The development of group treatment can be divided into three stages: pioneering, traditional, and modern. The pioneering stage began in 1906 and was a classroom method that dealt with psychosomatic symptomatology. It consisted of lectures, questions, and discussions. The traditional approach began in the 1930s and consisted of adapting classical therapy to the group setting. The central figure is the group leader, and the leader is the primary agent of change whose ultimate weapon is interpretation. It remains the predominant form of group treatment in this country. The modern approach took shape in the mid-1950s. It is marked by intense interactions between members. The group itself is the instrument of change, and the leader's function is to remove blocks against the free and open communication of feelings and thoughts among members. It emphasizes the emotional nature of relationships rather than insight.