Multiple sclerosis (MS) is a demyelinating disease that can damage neurons in the brain and spinal cord and is associated with several psychiatric disorders. However, few studies have evaluated the risk of psychiatric disorders in patients with MS by using a nationwide database. This study investigated the association between MS and the risk of psychiatric disorders.

Using data from the Taiwan National Health Insurance Research Database from 2000 to 2015, we identified 1066 patients with MS. After adjustment for confounding factors, Fine and Gray’s competing risk model was used to compare the risk of psychiatric disorders during 15 years of follow-up.

Of the patients with MS, 531 (4622.86 per 10⁵ person years) developed psychiatric disorders; by contrast, 891 of the 3198 controls (2485.31 per 10⁵ person years) developed psychiatric disorders. Fine and Gray’s competing risk model revealed an adjusted hazard ratio (HR) of 5.044 (95% confidence interval = 4.448–5.870, p < 0.001) after adjustment for all the covariates. MS was associated with depression, anxiety, bipolar disorder, sleep disorders, schizophrenia, schizophreniform disorder, and other psychotic disorders (adjusted HR: 12.464, 4.650, 6.987, 9.103, 2.552, 2.600, 2.441, and 2.574, respectively; all p < 0.001). Some disease-modifying drugs were associated with a lower risk of anxiety or depression.

Patients with MS were determined to have a higher risk of developing a wide range of psychiatric disorders.