Depersonalization, or feeling of unreality, is a symptom which may occur as part of several psychiatric conditions, such as hysteria, anxiety and obsessional states, and some forms of schizophrenia and endogenous depression. The true derealization-depersonalization syndrome, however, in which the unreality symptom is the primary disturbance, is a quite peculiar and distinctive condition, which has received scant attention in most psychiatric textbooks and which appears to be becoming increasingly common in practice.