INTRODUCTION: 

A psychotic relapse of schizophrenia is commonly preceded by nonpsychotic behavioral symptoms and signs, and detection of these early signs may enable prevention of relapse of schizophrenia. This study aimed to test the predictive validity of a Korean version of Early Signs Scale (K-ESS) for psychotic relapse for detecting the early signs. 

MATERIALS AND METHODS: 

In this multicenter noninterventional 52-week prospective study, outpatients diagnosed as having schizophrenia within 5 years were recruited. The K-ESS and Clinical Global Impression-Severity (CGI-S) scale were administered monthly until the end of the study or the relapse. The primary objective was to determine an optimal cutoff point of K-ESS score for prediction of psychotic relapse. The secondary objective was to assess the concurrent validity of the K-ESS using CGI-S scale. 

RESULTS: 

Among the 162 included patients, 14 (8.6%) relapsed during the 52-week study period. The optimal cutoff score of K-ESS was 15 with a sensitivity of 71.43% and a specificity of 52.70%, indicating poor predictive accuracy of K-ESS. A lower cutoff K-ESS score of 3 and a higher cutoff score of 28 were found in the subgroups with milder (CGI-S = 1-2) and severer (CGI-S = 3-4) symptom severity, respectively, with fair to good predictive accuracy. The K-ESS showed acceptable concurrent validity with CGI-S and concordance rate between self-rated and informant-rated scores. 

DISCUSSION: 

The predictive accuracy of K-ESS was limited by evaluation interval of a month. At least fortnightly follow-up would be needed for detection of early signs to prevent a psychotic relapse in schizophrenia.