Restless Legs Syndrome Linked to Much Higher Risk of Suicide and Self-Harm, Large Study Finds

Summary: New research indicates that restless legs syndrome (RLS) is associated with a substantially increased risk of suicide and self-harm.

Source: Penn State

Key finding: A large, claims-based study led by Penn State researchers found that people diagnosed with restless legs syndrome had nearly a threefold greater risk of suicide and self-harm compared with people without RLS, even after accounting for depression, insomnia and other common health conditions.

Researchers analyzed a large national insurance-claims database to investigate whether RLS is independently associated with suicide and self-harm. Using Truven Health MarketScan data covering 2006–2014, the team compared 24,179 people diagnosed with RLS to 145,194 age- and sex-matched people without the disorder. All participants were free of prior suicide or self-harm events at the start of the study.

Over an average follow-up of about 5.2 years, investigators identified 119 new cases of suicide or self-harm among the 169,373 study participants. After adjusting for lifestyle factors, chronic conditions, and medication use, having RLS was associated with an adjusted hazard ratio of approximately 2.66 (95% CI, 1.70–4.15) for suicide or self-harm. In additional analyses that excluded people with depression, insomnia, obstructive sleep apnea and other common chronic conditions, the association persisted and was even stronger (adjusted hazard ratio ≈ 4.14; 95% CI, 2.17–7.92).

Xiang Gao, associate professor of nutritional sciences and director of the Nutritional Epidemiology Lab at Penn State, emphasized the mental-health implications of the finding. With U.S. suicide rates increasing in recent years, Gao said clinicians should take the mental health of patients with RLS seriously and consider screening for suicide risk when appropriate.

“Our results suggest RLS is more than a physical disorder of the legs,” Gao said. “Because RLS is often underdiagnosed and suicide rates are rising, awareness of this association could help clinicians identify at-risk patients.”

Restless legs syndrome is a common neurologic condition, estimated to affect about 5% of Americans. It is characterized by an uncomfortable sensation in the legs that creates a compelling urge to move, typically worse at night and sometimes interfering with sleep. The underlying causes of RLS are not completely understood, but prior studies have linked it to iron deficiency and reduced dopamine activity in the brain. RLS has also been associated with higher risks of cardiovascular disease, hypertension and depression in previous research.

Muzi Na, Broadhurst Career Development Professor for the Study of Health Promotion and Disease Prevention at Penn State, noted that the study’s use of a very large data set—more than 200 million people available in the database—made it possible to test hypotheses that were previously unanswerable because of the low absolute rates of RLS diagnosis and suicide events.

“Even after we controlled for depression, insomnia and other conditions known to increase suicide risk, the link remained,” Na said. “That suggests RLS itself may contribute independently to the risk of suicide and self-harm, although the biological or psychosocial mechanisms are still unknown.”

The authors caution that while the association is robust in this claims-based cohort, observational research cannot prove causation. They recommend further studies to replicate these findings, explore underlying mechanisms, and determine whether screening and targeted interventions for people with RLS could reduce suicide and self-harm risk.

Source:
Penn State
Media contact:
Katie Bohn – Penn State
Image source:
The image is in the public domain.

Original research (open access):
“Association of Restless Legs Syndrome With Risk of Suicide and Self-harm.” Sheng Zhuang, MD; Muzi Na, PhD, MHS; John W. Winkelman, MD, PhD; Djibril Ba, MPH; Chun-Feng Liu, MD, PhD; Guodong Liu, PhD; Xiang Gao, MD, PhD. Published in JAMA Network Open. DOI: 10.1001/jamanetworkopen.2019.9966

Abstract (condensed):
This cohort study used national claims data to evaluate whether a diagnosis of RLS is associated with a higher risk of suicide and self-harm. The analysis included 24,179 participants with RLS and 145,194 matched participants without RLS, all free of suicide, self-harm, cardiovascular disease and cancer at baseline. During follow-up, individuals with RLS had a higher risk of suicide or self-harm after adjustment for demographic factors, lifestyle, chronic disease and medication use. The association remained after excluding participants with depression, insomnia and other common conditions. The authors conclude that RLS is associated with an increased risk of suicide and self-harm independent of most identified diseases and conditions, and they call for additional research to confirm these findings and to investigate mechanisms.