Consistency of symptomatic dimensions of schizophrenia over 20 years

Our goal was to analyze the consistency of the symptomatic dimensions of schizophrenia over the course of our 20-year prospective study. We investigated a sample of patients diagnosed with Diagnostic and Statistical Manual of Mental Disorders Third version (DSM III) schizophrenia and later re-diagnosed with Diagnostic and Statistical Manual of Mental Disorders Fourth version (DSM IV) at four intervals: three, seven, twelve and twenty years from their first hospitalization. The severity of symptoms was assessed using expanded version of Brief Psychiatric Rating Scale (BPRS - E). Exploratory factor analyses and then confirmatory factor analyses were conducted. A four-factor structure was found, with positive, negative, depressive and excitement factors. In the confirmatory factor analysis, the only symptomatic dimension confirmed at all follow-ups was the negative factor (emotional withdrawal, motor retardation, blunted affect and conceptual disorganization) as derived from the 20-year follow up in exploratory factor analysis. The positive syndrome derived from the three-year follow-up (hostility, suspiciousness, unusual thought content and hallucinations) was confirmed at the seven- and 20-year follow-ups. In the depressive syndrome the model from the 12-year follow-up (guilt, depression, suicidality, anxiety and somatic concern) was confirmed for the follow-ups after seven and 20 years. As regards the excitement syndrome, we confirmed the model from the three-year follow-up (motor hyperactivity, elated mood, conceptual disorganization, excitement) at the follow-ups at seven and 12 years.