Some of them do it in the first place by diagnosis, others by age, by social, economic and intellectual conditions, or by the same necessity. Groups can be open or closed, homogeneous or heterogeneous, depending on how the therapist wishes to stimulate or maintain patterns of behavior. The use of different people with opposite problems tends to develop a maximum of stimulation and acts in the direction of the discharge of tensions in the group. The number of similar individuals with the same type of problems tends to encourage the suppression of other behavior patterns, and if people are different with similar or opposite problems. Balance with patients of similar, opposing or different types tends to favor the therapeutic process.…