Affective processes in the onset and persistence of psychosis.

OBJECTIVES: Cognitive models suggest that beliefs and appraisal processes are crucially important in the onset and persistence of psychosis. This study investigated whether (i) neuroticism increases the risk for development of psychotic symptoms, and (ii) a delusional interpretation and/or a depressed response to hallucinatory experiences predicts the onset of psychotic disorder.
METHOD: A general population sample with no lifetime evidence of any psychotic disorder was interviewed with the Composite International Diagnostic Interview Schedule (CIDI) at baseline and 1 and 3 years later. At year 3, individuals with CIDI evidence of psychotic symptoms were interviewed by clinicians to identify onset of psychotic disorder.
RESULTS: Baseline level of neuroticism increases the risk for incident psychotic symptoms. Given the presence of hallucinatory experiences at baseline, the increase in risk of having the psychosis outcome was much higher in the group with delusional ideation or depressed mood at year 1 than in those without delusional ideation or depressed mood.
CONCLUSION: A cognitive style characterised by a tendency to worry increases the risk for newly developed psychotic symptoms. Individuals who report hallucinatory experiences and react to these with a delusional interpretation and/or negative emotional states have an increased risk for developing clinical psychosis.