Clinical characteristic of prodromal symptoms between bipolar I and II disorder among Chinese patients: a retrospective study

Abstract Background This study aimed to identify the clinical characteristic of prodromal symptoms in Chinese patients with bipolar disorder (BD), prior to the first affective episode. It further aimed to characterize the prodromal traits between bipolar disorder type I (BD-I) and type II (BD-II). Methods 120 individuals with BD-I (n = 92) and BD- II (n = 28) were recruited to the study. Semi-structured interviews were then administered to evaluate prodromal symptoms in patients, within 3 years of BD onset, by using the Bipolar Prodrome Symptom Scale-Retrospective (BPSS-R). Results In the prodromal phase of the first depressive episode, patients with BD-II experienced more prodromal symptoms (p = 0.0028) compared to BD-I. Additionally, more frequent predictors were reported in patients with BD-II than BD-I including educational and occupational dysfunction (p = 0.0023), social isolation (p