There appears to be a clinical sub-entity in the psychogenic or "reaction to environment" group of psychoses, in which the chief symptoms are persecutory delusions, with or without hallucinations, and without obvious personality or intellectual changes, occurrring in highly moral women, and becoming apparent during the fifth and sixth decades after a long prodromal period, the change from normal to psychopathic being so gradual that relatives have found difficulty in fixing the date of onset and persons who have but slight contact with the patient are not aware that the individual is suffering from a psychosis. A close study of many cases admitted to our mental hospitals over a period years has convinced us that there is a specific etiological factor, among others common to the group as a whole. This so-called specific factor we believe to be an overt or imagined sinful act on the part of the patient, which is not sinful to the patient, however, as she either projects the blame on others or denies that it would have been consciously desired by her. The situation is thus not dealt with adequately and honestly, and a state of emotional unrest is produced. As a quietus to conscience a persecutory delusional trend is developed slowly and progressively until a well-marked psychosis results.If our deductions are correct, we feel that mental hygiene instruction to the laity can utilize the concrete suggestion of greater honesty with ourselves in dealing with problems relating to temptation, sin and conscience.