Severity of depressive episodes according to ICD-10: prediction of risk of relapse and suicide

Abstract

BackgroundThe ICD–10 categorisation of severity of depression into mild, moderate and severe depressive episodes has not been validated.AimsTo validate the ICD–10 categorisation of severity of depression by estimating its predictive ability on the course of illness and suicidal outcome.MethodAll psychiatric in-patients in Denmark who had received a diagnosis of a single depressive episode at their first discharge between 1994 and 1999 were identified. The risk of relapse and the risk of suicide were compared for patients discharged with an ICD–10 diagnosis of a single mild, moderate or severe depressive episode.ResultsAt their first discharge, 1103 patients had an ICD–10 diagnosis of mild depressive episode, 3182 had a diagnosis of moderate depressive episode and 2914 had a diagnosis of severe depressive episode. The risk of relapse and the risk of suicide were significantly different for the three types of depression – increasing from mild to moderate to severe depressive episode.ConclusionsThe ICD–10 way of grading severity is clinically useful and should be preserved in future versions.