Deafness and psychiatric illness.

Review of the literature concerning the relationship between deafness and psychiatric disorder reveals differences in the pattern of illness depending on the severity of deafness and the age of onset. In particular, the prevalence of schizophrenia in the prelingually deaf is similar to that found in the normal population, whereas the hard of hearing are over-represented among samples of patients suffering from paranoid psychoses in later life. Possible modes of action of long-standing hearing loss in the aetiology of paranoid illnesses are considered: the psychological and social consequences of deafness, the possible contribution of sensory deprivation phenomena, and the interference of hearing loss in attention, perception and communication. Finally, possible future lines of research are suggested.