Episode accumulation associated with hastened recurrence and delayed recovery in bipolar disorder

Aims: Assess episode accumulation (>= 10 prior mood episodes) associations with demographic/baseline clinical characteristics and mood episode recurrence/recovery in bipolar disorder (BD). Methods: Stanford BD Clinic outpatients enrolled during 2000-2011 were assessed with Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation. Among recovered and syndromal mood episode patients, we assessed episode accumulation associations with demographic/baseline clinical characteristics and with recurrence/recovery (by Kaplan-Meier survival analyses, with mediators assessed with Cox Proportional Hazard Ratio (HR) analyses). Results: Among all 450 BD outpatients, almost twice as many had versus lacked episode accumulation (65.8% versus 34.2%), which was less common among 92 recovered versus 193 syndromal mood episode patients (51.1% versus 69.9%). Among recovered patients, episode accumulation was associated with 14/18 (77.7%) demographic/other baseline clinical characteristics, and hastened mood episode recurrence. Among syndromal mood episode patients, episode accumulation was associated with 13/18 (72.2%) demographic/other baseline clinical characteristics, and delayed mood episode recovery. Limitations: American tertiary BD clinic referral sample. Conclusion: Studies are needed to confirm episode accumulation is associated with hastened mood episode recurrence and delayed mood episode recovery in BD, and to further explore its' associations with hastened mood elevation recurrence and delayed recovery from depressive and mood elevation episodes, considered separately.