How frequent is chronic multiyear delusional activity and recovery in schizophrenia: a 20-year multi-follow-up.

To determine how frequent chronic multiyear delusional activity is in modern-day schizophrenia, we studied 200 patients over a 20-year period. We also studied the relation of delusions to hallucinations and thought disorder-disorganization, to work disability, and to later periods of global recovery and assessed several protective factors against delusional activity. The sample was assessed 6 times over 20 years and includes 43 patients with schizophrenia. Participants were evaluated at each follow-up for delusions, hallucinations, thought disorder-disorganization, work disability, and global recovery. Possible protective factors were assessed prospectively at index hospitalization. Twenty-six percent of the patients with schizophrenia were delusional at all follow-ups over the 20 years. Overall, 57% had frequently recurring or persistent delusions. A subgroup of over 25% of the schizophrenia patients had no delusional activity at any of the 6 follow-ups over 20 years. Schizophrenia patients with posthospital delusional activity had increased work disability (P < .05). Delusions that persisted after the acute phase in schizophrenia patients predicted a lower likelihood of future global recovery (P < .01). In conclusion, slightly over half of modern-day schizophrenia patients are vulnerable to frequent or "chronic" delusional activity after the acute phase. Schizophreniform patients and other types of psychotic disorders are vulnerable to posthospital delusional activity, but less frequently, less severely, and more episodically. Delusional activity is associated with work disability. Internal factors such as good premorbid developmental achievements and favorable prognostic factors are protective factors that reduce the probability of chronic multiyear, delusional activity in schizophrenia (P < .01).