AIM: Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic pain syndrome of unknown etiology that primarily affects women. Using a longitudinal follow-up design, this study aimed to examine the risk of depressive disorder (DD) among women with BPS/IC compared to the general population during a 1-year period following their diagnosis. METHOD: This study used data from the Taiwan "Longitudinal Health Insurance Database." A total of 832 patients with BPS/IC were included in the study group and 4,160 matched non-BPS/IC enrollees were included as the comparison group. Each patient (n = 4,992) was individually tracked for a 1-year period to identify those who subsequently received a diagnosis of DD. Cox proportional hazards regressions (stratified by age group and the index year) were used to estimate the risk of subsequent DD following a diagnosis of BPS/IC. RESULTS: We found that during the 1-year follow-up, the incidence rate of DD was 4.69 (95% CI: 3.38-6.34) per 100 person-years in patients with BPS/IC and 0.94 (95% CI: 0.68-1.27) per 100 person-years in comparison patients. The hazard ratio (HR) of DD during the 1-year follow-up period for patients with BPS/IC was 5.06 (95% CI: 3.21-7.96, P < 0.001) that of comparison patients after adjusting for patient monthly income, geographic location, and urbanization level. The adjusted HR for DD associated with BPS/IC was 10.33 for patients aged between 40 and 49 (95% CI: 3.68-29.04). CONCLUSION: Our study demonstrated that there is an increased risk for being diagnosed with DD during the first year subsequent to being diagnosed with IC/PBS.