An empirical method to identify patterns in the course of psychotic episodes of people with schizophrenia

Objective: This paper illustrates the process of constructing, selecting and applying simple measures in order to empirically derive patterns of course of psychotic episodes in schizophrenia.Method: Data were collected with a composite instrument constructed for a multi-centre, follow-up randomized controlled trial of adherence therapy for people with schizophrenia. The instrument included a retrospective weekly assessment of psychotic/non-psychotic status, which was used to derive the measures, and the DSM-IV course specifiers.Results: The measures discriminated well between different course patterns and identified homogeneous clusters of subjects which correlated with the groups derived from the DSM-IV course specifiers.Conclusions: The new measures provide an empirical basis to identify specific patterns of course and to differentiate patients according to pre-defined criteria. They can be used in follow-up studies as measures of outcome, to investigate correlations between variables and to identify potential predictors of outcome.