The heterogeneous early illness courses of Korean patients with bipolar disorders – replication of the stage model

Background: Clinical staging of bipolar disorder requires application of real-world data, as the next step in hypothesis. This study used the staging model to analyze the long-term course of BD in Korean patients based on clinical features and treatment responses to map the progression of bipolar illness from the early phase after the onset of illness. Methods A total of 136 patients diagnosed with BD-I (n = 62) or BD-II (n = 74) were recruited. Their progressive stages were retrospectively evaluated. The multi-state model was used to calculate the probability of progression to each stage. We calculated the hazard ratio of covariates expected to influence different courses of BD. Using the Alda score, we compared the long-term response to mood stabilizers depending on the current stage. Results Several sub-populations showed a varied course during the first five years after the onset of illness, with 41.5% remaining in stage 2 and 53% progressing to higher stages with shortening of time for transition. The profile of patients with BD-II differed profile from BD-I, suggesting biologically distinct groups. The group with Obsessive-compulsive Disorder (OCD) had higher risk in relation to both recurrent course (stage 3a or 3b) and malignant course (stage 3c or 4). Early age of onset, shorter lifetime duration, older age at the start of medication, and poor response to lithium affect long-term therapeutic outcomes. Conclusions The staging model encompasses early to recurrent and chronic courses of BD. The stage progression pattern differed in BD-Ⅰ and BD-Ⅱ patients from the early phase. Previous findings related to long-term course of BD enabled expansion of model parameters.