The British Journal of Psychiatry
The Phenomenology of Hallucinations as an Aid to Differential Diagnosis


This phenomenological study systematically compares the characteristics of 202 hallucinations as reported by 60 mental hospital patients, subdivided by diagnosis into manic-depressives, organics, paranoids, and schizophrenics. The phenomenological characteristics of these hallucinations were compared in terms of: (a) clinical descriptions of extreme frequencies; (b) multiple rank ordering of frequencies to obtain weighted discriminatory indicators; (c) discriminant function analysis. The findings suggest that phenomenological characteristics of hallucinations may be used as discriminatory indicators for differential diagnosis among psychotics; that some parameters are better than others for discriminating diagnostic groups; and that the best general discriminators are, in descending order, the number of hallucinations, their duration, the import of their content for the patient, the extent to which the patient believes that others share his hallucinatory experience, and the extent to which the hallucination affects his observable behaviour.