Identification and medical utilization of newly diagnosed panic disorder: A Nationwide case-control study

Objective: Ascertaining comorbid illnesses and patterns of medical utilization early in the course of psychiatric illness can help identify patients with panic disorder. We investigated how such cases were diagnosed and the comorbidities associated with newly diagnosed panic disorder in a nationwide database. Methods: We enrolled a large representative cohort of the general population in Taiwan (N = 1000,000) and selected 9759 cases of panic disorder from January 1, 2000 to December 31, 2013. The distribution of the departments in which the cases were identified and the medical utilization 12 months before diagnosis were analyzed. Based on a nested case control-study, four controls were randomly selected for each case and matched for sex, age, and incidence year. Conditional logistic regression was used to explore the factors associated with newly-diagnosed panic disorder such as demographic factors, concomitant medications, and physical and psychiatric comorbidities. Results: Most (58.5%) cases of panic disorder were diagnosed in the psychiatry department, whereas only 3.7% were identified in the emergency department. Before diagnosis, the patients frequently visited the departments of internal medicine, family practice, and Chinese herbal medicine. A multivariate analysis revealed a higher number of physical and psychiatric comorbidities before diagnosis in the cases compared with the controls, especially depressive disorder and other anxiety disorders. Conclusions: Individuals with certain comorbidities and patterns of medical utilization are more likely to be diagnosed with panic disorder. We suggest providing more training to general practitioners and emergency physicians for the early diagnosis of panic disorder.