ABSTRACT
BACKGROUND: Panic disorder (PD) and major depressive disorder (MDD) can occur concurrently, despite different clinical manifestations. Because MDD and PD patients tend to have more complicated conditions, understanding the co-occurrence and pattern of these conditions is important. Here, we investigated the influence of PD and MDD on each other, with respect to time interval. METHODS: Data from three national representative surveys were pooled (total 18,807 respondents), and the age of onset (AOO) of PD and MDD was analyzed. We performed Kaplan-Meier analysis to estimate separate survival functions, using the AOO of MDD and PD as the outcome. To understand the temporal effect of other disorders, we used a Cox proportional hazard model to estimate the hazard ratios for the onset of MDD/PD with other comorbidities as time-dependent covariates. RESULTS: PD elevated the risk of subsequent MDD by 1.5-fold, whereas MDD elevated the risk of subsequent PD by 3.8-fold. The effect of such an elevation risk was significant for up to 2 years. CONCLUSION: The results revealed a bidirectional relationship between MDD and PD. Each disease represents a risk of a subsequent occurrence of the other, which lasts for a considerable duration.