By Carolyn Crist

(Reuters Health) – Having a diagnosis of restless legs syndrome may also signal an increased risk for self-harm, suicidal thoughts and suicide, a study based on U.S. insurance claims suggests.

Restless legs syndrome (RLS) – an irresistible urge to move one’s legs that occurs even while a person is asleep – is common but poorly understood. Among 169,000 healthy patients included in the analysis, some 24,000 had been diagnosed with RLS. Over a six-year follow-up, those with RLS were over two and a half times as likely as those without it to harm themselves or experience suicidal thinking or attempts, researchers report in JAMA Network Open.

“RLS is one of the most common sleep disorders and movement disorders, affecting about 5% of U.S. adults,” said senior study author Dr. Xiang Gao of the Pennsylvania State University College of Medicine in University Park.

RLS is considered a neurologic disorder. It has been associated with disturbed sleep and with depression, the study team notes.

“We’ve also published several studies that show RLS is associated with a high risk of developing depression,” Gao noted in an email.

With U.S. suicide rates rising, Gao and colleagues wanted to explore links between RLS and suicide risk. They analyzed national health claims data from 2006-2014 for adults enrolled in U.S. commercial medical, pharmacy and dental insurance plans. Along with 24,000 people with a diagnosis of RLS, they included 145,000 similar people without RLS. All 169,000 individuals had no history of heart disease, cancer, self-harm or suicidal thinking at the beginning of the study.

The researchers found that people with RLS were more likely to be diagnosed with depression and to use antidepressant medicines, which could suggest poorer mental health. Individuals with RLS were also more likely to live in a rural area, to consume alcohol, to have chronic obstructive pulmonary disease and to report other chronic conditions such as diabetes, hypertension, sleep apnea, insomnia, kidney disease and neurological disorders.

There were 119 suicide and self-harm cases during the study. After researchers accounted for other factors that could influence self-harm and suicide risk, including alcohol abuse, obesity, depression, insomnia and diabetes, they found that people with RLS were 2.66 times more likely as those without RLS to be among these cases.

The higher risk of suicide and self-harm was present among people with an RLS diagnosis who were receiving treatment for the syndrome and those not receiving a prescribed treatment.

When researchers excluded people with depression, insomnia, obstructive sleep apnea and chronic medication use from their calculations, the association between RLS and suicide or self-harm not only persisted, it grew in strength to a more than four-fold risk with RLS, the authors note.

“It suggests that RLS, per se, could be a risk factor for suicide or self-harm, independent of depression and sleep disorders which are commonly seen among RLS patients,” Gao said.

The study wasn’t designed to determine how RLS might directly or indirectly contribute to risks for suicidal thinking or self-harm. And medical insurance claims data may miss people with undiagnosed RLS and those with undiagnosed suicidal or self-harm episodes, the study team notes.

“RLS has annoying symptoms that patients can’t stand. However, because it’s not well-known to folks, even among clinicians, it can be misdiagnosed and treated the wrong way,” said Dr. Heon-Jeong Lee of the Korea University College of Medicine in Seoul, who wasn’t involved in the study.

“RLS symptoms and mental distress are more likely to worsen if you increase the amount of drugs to treat symptoms such as insomnia and depression,” Lee told Reuters Health by email.

RLS tends to disrupt the circadian rhythm, Lee added, which compounds the symptoms. Lifestyle changes such as getting regular exercise can often help people get better sleep by tiring them out.

“Above all, having a regular lifestyle rhythm is important to prevent the aggravation of RLS,” Lee said. “Symptoms of mild RLS are not a problem if the sleep needs increase due to sufficient activity during the day.”

SOURCE: JAMA Network Open, online August 23, 2019.