Studies of many patients before and after lobotomy indicate complex relationships between history, personality and behavioral response after frontal lobe surgery. It has been shown, for example, that postoperative changes may move in either direction along a given parameter–sometimes favorable and sometimes unfavorable. For example, worry and fear were greatly allayed after operation, yet not produced at all by operation. On the other hand, outspokenness existing before operation was removed as a symptom in one-third of the cases after operation, yet in a half of the cases in which it was of no significance preoperatively, outspokenness was produced as a postoperative, undesired characteristic.It is possible to illustrate poignantly how a given change, such as an increase in aggressiveness or dominance, in some instances pleased the family, and in others caused constraints. Conversely, a decrease in aggressiveness or dominance could either please or displease the important persons in the patient's family circle. Social interaction studies showed that there was considerable dependence of postoperative change on preoperative level or type of socialization. In general, the tendency was towards a normalization of behavior: patients who showed excessive activity became more moderate, and patients with deficient activity tended to have a release of this activity after operation.Concerning the problem of prediction of mental status after operation, it was noted that the primary predictors of good outcome were rapid onset, high tension, insight present, hallucinations absent, verbalness and friendliness, and, finally, a diagnosis of psychoneurosis rather than schizophrenia.The experience suggests that the reactions to severe brain cutting are not to be predicted alone on the basis of the type and amount of brain cut or destroyed, but in relation to many factors from the background and personality of the patient.Abstract Teaser