BACKGROUND Mental disorders and cardiovascular diseases are closely related. However, a paucity of information on the risk of incident atrial fibrillation (AF) in patients with mental disorders exists.

OBJECTIVE We aimed to assess the association between mental disorders and the risk of AF, particularly in young adults.

METHODS Using the Korean National Health Insurance Database between 2009 and 2012, we identified adults aged 20-39 years without a history of AF and who have been diagnosed with mental disorders. Mental disorders were defined as having one of the following diagnoses: depression, insomnia, anxiety disorder, bipolar disorder, or schizophrenia. The primary outcome was new-onset AF during follow-up.

RESULTS A total of 6,576,582 subjects (mean age 30.9 ± 5.0 years; 3,919,339 [59.6%] men) were included. Among the total population, 10% had mental disorders. During the follow-up period, 8932 incident AF events occurred. Patients with mental disorders showed a higher AF incidence than did those without (25.4 per 100,000 person-years vs 17.7 per 100,000 person-years). After multivariable adjustment, mental disorders were associated with a significantly higher risk of AF (adjusted hazard ratio 1.526; 95% confidence interval 1.436-1.621). Patients with bipolar disorder or schizophrenia had a 2-fold higher risk of AF and those with depression, insomnia, and anxiety disorder had a 1.5- to 1.7-fold higher risk of AF than did those without mental disorders.

CONCLUSION Young adults diagnosed with mental disorders have a higher risk of incident AF. Awareness for AF in high-risk populations should thus be considered.