A more subtle analysis in terms of symptom domains or diagnosis-related outcomes could make it possible to compare the effects of diagnosis-mixed PE on the level of syndromes or disorders. It is still unexplored which patients benefit remarkably more by a group that is specifically tailored to their personal or illness-dependent characteristics, and exactly which patient-related trait should serve as the most promising criterion for a diversification of PE groups. Besides diagnostic categories, for example, sex, age and the educational background are worthy of consideration. Larger study samples and longer follow-up periods may allow conclusions on subgroups and promote statistical significance, respectively.