Prevalence of Generalized Anxiety Disorder in Japan: A General Population Survey.

Purpose: Generalized anxiety disorder (GAD) is among the most prevalent and highly disabling mental health conditions that negatively impacts patient's quality of life (QOL) and disrupts activities of daily living. However, the recognition of GAD is difficult due to substantial overlap with other mental disorders. The purpose of this study was to estimate the prevalence of GAD, assess QOL of probable GAD patients in Japan, and gain insights on the status of visiting medical institutions as well as their recognition/awareness of the disorder.

Patients And Methods: We conducted a web-based cross-sectional survey of 20,009 participants using a questionnaire with approximately 30 single/multiple choice or open-ended questions in Japanese.

Results: Overall prevalence of GAD based on Generalized Anxiety Disorder 7-item (GAD-7) cutoff score of ≥10 and questionnaires developed with reference to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria was 7.6% (n=1530) and 6.0% (n=1197), respectively. The degree of coincidence between GAD diagnosis by DSM-5 criteria and GAD-7 scores was moderate (Cohen's Kappa=0.47, <0.01). Younger people reported a substantially higher prevalence of GAD compared to older. QOL scores assessed using EuroQol 5 dimensions 5-level and EuroQol Visual Analog Scale were substantially lower in probable GAD patients than those with GAD-7<10. Anxiety/depression and pain/discomfort were the most prevalent issues and depression was the most reported comorbidity for the probable GAD patients. Probable GAD patients "currently visiting medical institutions" for anxiety or other mental issues were 27.6% (422/1530); a majority had seen specialists. Most of the probable GAD patients had never heard of the disease.

Conclusion: We found higher prevalence of GAD and lower QOL of probable GAD patients in Japan. There is a need for creating awareness about GAD among the general population and developing clinical guidelines on GAD in Japan so that physicians can educate their patients.