Insight as a Predictor of the Outcome of First-Episode Nonaffective Psychosis in a Prospective Cohort Study in England

Abstract

To estimate the effect of insight on time to relapse and readmission and on social function and symptoms after following up a cohort of first-episodes of nonaffective psychosis for 18 months. Patients with first episodes of DSM-IV schizophreniform disorder, schizophrenia, schizoaffective disorder, delusional disorder, and psychosis not otherwise specified (excluding primary substance-induced or organic psychoses), aged 16 to 65 years, were recruited over the 26 months from July 1996 to September 1998 from consecutive admissions to day-patient and inpatient units in England with a catchment area population of 2.3 million. They were interviewed with the Positive and Negative Syndrome Scale, Birchwood Insight Scale, and Social Functioning Scale at baseline and 18 months. The hazard ratio for relapse, per unit increase in the insight score, was estimated in a Cox proportional hazards model to be 0.943 (95% CI = 0.892 to 0.996; p = .035). Those with the best insight scores had an estimated rate of relapse that was 39% of that of those with the worst scores (95% CI = 16% to 93%). Readmission was highly correlated with relapse, so poor insight also predicted readmission (hazard ratio 0.934; 95% CI = 0.876 to 0.996; p = .036). However, insight did not independently predict symptoms or social function after adjustment for other predictors of outcome. Insight predicted both relapse and readmission. The details of the beliefs and assumptions determining outcome remain unclear, but intervening to alter them appears to be justified.