Long‐term course and outcome in delusional disorder

Out of 301 first‐time admitted patients with delusional psychoses, 71 met Kendler's criteria of delusional disorder (DD) and 137 met the ICD‐9 criteria of schizophrenia (S). DD was subdivided according to operational criteria into reactive delusional disorder (RDD) with precipitating factors ( n = 31) and non‐RDD ( n = 40). At follow‐up after 22‐39 years, 20 RDD patients, 21 non‐RDD patients and 85 S patients were personally interviewed. The delusions had faded in 61% of DD cases, were unchanged in 17%, and more prominent in another 17%. Recovery was recorded in 37%, mild defect in 32%, moderate impairment in 10%, and severe impairment in 22% of DD patients. Outcome was more favourable in DD compared with S, in RDD compared with non‐RDD, and in non‐RDD compared with S. The study supports distinctions between DD and S, RDD and non‐RDD, and non‐RDD and S based on course and outcome.