Some patterns of deranged function—epilepsy, schizophrenia—have been enshrined as diseases; others, such as depersonalization, have, by and large, escaped this fetter. This is perhaps why there has been no difficulty in accepting that depersonalization, being a pattern of disordered function, can occur in conditions of very different aetiology. It is seen in temporal lobe epilepsy (12), temporal lobe migrane (22), depression (8), LSD intoxication (20), schizophrenia (1), phobic anxiety states (15), sleep deprivation (2) and the hypnagogic state. Shorvon (21) reported cases of depersonalization occurring in the apparent absence of other psychiatric disorder, and Davison (4) investigated in detail seven such cases. Finally the occurrence of depersonalization in people not attending psychiatric or neurological clinics is now well attested (13, 5, 18, 6).