Scattered throughout the literature on the psychiatric aspects of asthma are reports of cases where the psychiatric disturbance was severe enough to be described as “psychotic” (Reichmann, 1922; Hansen, 1929; St. Saxl, 1933; Oberndorf, 1935). The term “psychotic” was used in the sense that the psychiatric diagnosis was either that of manic-depressive psychosis, schizophrenia, or paranoid psychosis. It has been postulated, moreover, that the co-existence of a psychosis and attacks of asthma was no chance relationship, and that there was an intimate link between the psychosis and the somatic disturbance. This relationship, it has been said, is of considerable theoretical significance. Appel and Rosen (1950), for example, consider that “there is a reciprocal relationship between the so-called physical manifestations of psychosomatic illness and the psychological manifestations of psychiatric illness.” This concept is also held to apply in disorders other than asthma—in ulcerative colitis, rheumatoid arthritis, and in certain skin disorders. The treatment of such disorders psycho-therapeutically is said to result at times in an alleviation of the physical disorder, but the concomitant development of a psychotic reaction (Appel and Rosen, 1950; Lindemann, 1950). During the past three years an investigation of patients suffering from asthmatic attacks has been in progress, and the opportunity has arisen to examine these points on a fairly large case material. The present paper reports an attempt to investigate scientifically some aspects of the relationship between asthma and psychosis.