Background: How insight, paranoia and depression evolve in relation to each other during and after the first episode of schizophrenia is poorly understood but of clinical importance.
Method: Serial assessments over 18 months were made using multiple instruments in a consecutive sample of 257 patients with first episode DSM-IV non-affective psychosis. Repeated measures of paranoia, insight, depression and self-esteem were analysed using structural equation modelling, to examine the direction of relationships over time after controlling for confounds.
Results: Depression was predicted directly by greater insight, particularly at baseline, and by greater paranoia at every stage of follow-up. Neither relationship was mediated by self-esteem, although there was a weak association of lower self-esteem with greater depression and better insight. Paranoia was not strongly associated with insight. Duration of untreated psychosis and substance use at baseline predicted depression at 18 months.
Conclusions: In first-episode psychosis, good insight predicts depression. Subsequently, paranoia is the strongest predictor. Neither effect is mediated by low self-esteem. Effective treatment of positive symptoms is important in preventing and treating low mood in early schizophrenia.