Regular intake of non-opioid analgesics is associated with an increased risk of restless legs syndrome in patients maintained on antidepressants.

OBJECTIVE: To evaluate prevalence and risk factors of restless legs syndrome (RLS) in secondary-care patients maintained on tricyclic and serotonin reuptake inhibiting antidepressants.

METHOD: A total of 243 subjects with affective and anxiety disorders were interviewed for symptoms of RLS before and after at least 6 months of antidepressant pharmacotherapy within a naturalistic study. Logistic regression analysis was applied to adjust for the effects of age, gender, comorbidities, and the most frequent co-medications.

RESULTS: The overall prevalence of RLS was 27%. In the RLS-affected patients, regular use or overuse of non-opioid analgesics frequently combined with caffeine was the major risk factor which significantly correlated with psychiatric and medical comorbidity. In a subsample of 172 patients who had seldom taken analgesics the prevalence of RLS was 9%, which corresponds with its prevalence in the general population.

CONCLUSION: Neither antidepressants nor neuroleptics but non-opioid analgesics appear to be a major risk factor of RLS. Their regular use should be considered in studies of RLS-patients on psychotropic or other drugs. In this sample of secondary-care patients, ICD-10 classified depression or anxiety per se did not appear to be a risk factor of RLS.