Outcome in schizophrenia and related disorders compared between developing and developed countries - A recursive partitioning re-analysis of the WHO DOSMD data

Background Data on the two-year pattern of course of illness have been collected in the WHO study of the Determinants of Outcomes of Severe Mental Disorder (DOSMD). These data are reanalysed using recursive partitioning, a method not yet applied to psychiatric data, to test the hypothesis that subjects from participating centres in developing countries had better outcomes than those in developed countries. Method Subjects were those from the DOSMD study For whom two-year follow-up data were available (n=1056). The classification and regression trees recursive partitioning technique was used to examine the predictor variables associated with the outcome variable two-year pattern of course. Results Pattern of course was best predicted by centre, but two developed centres (Prague and Nottingham) grouped with the developing country centres excluding Call, having better outcomes than in the remaining developed country centres and Cali. Type of onset (insidious v. non-insidious) was the next strongest predictor, but its effect differed across these two centre groupings. Effects for some groups were modified by other predictor variables, including age, child and/or adolescent problems, and gender. Conclusions The predominant predictor effects on two-year pattern of course continued to be centre and type of onset, but complex interactions between these variables and other predictor variables are seen in specific centre groupings not strictly defined by 'developing' and 'developed'.