Objectives: ：This study investigated lifetime experiences of trauma, treatment retention, and psychiatric symptoms among outpatients with panic disorder after initiation of pharmacotherapy. Our research hypothesis was that panic patients with childhood trauma would display more severe symptoms and less treatment retention compared to those without such history. Methods: ：A total of 135 first-visit outpatients with DSM-IV panic disorder were approached during the period from March 2012 to August 2016. Fifty-three patients (39%) either refused or returned incomplete questionnaires, leading to a final sample size of 82. Participants completed the Trauma History Screen, the Beck Depression Inventory, the Beck Anxiety Inventory, and the Abbreviated PTSD checklist. Results: ：The number of lifetime trauma was significantly correlated with treatment retention (rho=-0.269, p=0.015). Among subtypes of trauma, only childhood physical abuse was significantly correlated with treatment retention (rho=-0.298, p=0.007). Conclusions ：Our results indicated that psychological trauma, particularly of an interpersonal nature from childhood, can affect pharmacotherapy treatment retention in panic disorder. This may be mediated by poor patient- doctor relationships originating from trust issues among childhood trauma survivors or lack of perceived improvement due to the more severe symptoms and unfavorable course experienced by those with childhood trauma. Further studies are needed to explore the reasons for poor treatment adherence in this population.