Psychotic states due mainly, but not exclusively, to unusual external circumstances are well known, and are commonly exemplified by such mental disorders as are occasionally met with in persons in prison, or those morbidly homesick, or suffering under the strain and stress of advanced deafness. In the great majority of these instances, however, the external conditions represent only an additional, precipitating aetiological factor which is operating as a trigger mechanism to a mental derangement of non-specific character already present in a latent state. It may therefore be of some theoretical and practical interest to report on a group of acute and subacute psychotic states whose history, features, course and outcome characterize them as constituting a readily recognizable clinical entity of purely psychological, situational origin.