Involutional Psychosis: Some New Aetiological Considerations

Abstract

In this paper age- and sex-specific first admission rates to hospital for involutional psychoses (Malzberg, 1955), are submitted to the same type of mathematical analysis as that used in the two preceding papers. To judge from the nature of the fit between the observed rates (for both sexes) and a highly restrictive mathematical function it seems probable that this diagnostic category—as used in New York State, 1949 to 1951, and by Kallmann (1953)—corresponds to a definite organic disease. Its relationship to the so-called involutional phase of life would appear to be coincidental. The disease is confined to a genetically specific sub-population and the phenotypic expression apparently requires the accumulation of 12 random events. Certain statistical properties of the system affected by these random events are closely similar to those of the “lymphoid system” in autoimmunity. The hypothesis can therefore be entertained that involutional psychosis—together with manic depressive psychosis and schizophrenia—is fundamentally an autoimmune disorder. However the primary pathogenic agent and its “target” organ have not yet been identified and the disease could equally well arise from stochastic disturbances in some other, hitherto unidentified, system, certain statistical characteristics of which are similar to those of the lymphoid system.