One aim of the European prediction of psychosis study (EPOS) has been to evaluate the clinical course of putatively prodromal patients in terms of psychopathology.

245 patients at risk for psychosis defined by attenuated positive symptoms, brief limited psychotic symptoms, a state/ trait combination or cognitive-perceptive basic symptoms was recruited in six centres in four countries. The Structured Interview for Prodromal Syndromes (SIPS) and the Bonn Scale for the Assessment of Basic Symptoms – Prediction List (BSABS-P) were employed. Follow-up was scheduled after 9 months (t1) and 18 months.

In total, 40 patients developed a psychosis (P). Compared to those without a transition (NP), P showed significantly higher SIPS scores at baseline. The same applied to the BSABS-P sub-scores 'cognitive perception disturbances' and 'cognitive motor disturbances'. The P sub-group developing psychosis after t1 showed no significant change of the SIPS positive (SIPS-P) sub-score or of any BSABS-P score from baseline to t1, whereas all scores improved in the NP group. At t1, SIPS-P and BSABS-P sub-score 'cognitive thought disturbances' were significantly lower in those later becoming psychotic.

Patients at risk showing a transition to psychosis during exhibited a pronounced psychopathology at baseline. Also, the positive symptom scores did not significantly improve during 1st follow-up, whereas those patients with no transition during the complete follow-up showed an improvement of all scores. As EPOS is a naturalistic study, different treatments have been performed in a considerable portion of the patients and association with course awaits further analysis.