People with restless leg syndrome have an almost threefold higher risk of suicide , according to new research.
Doctors need to pay special attention to the mental health of patients with the torturous condition, warn scientists.
The common neurological disorder causes an irresistible urge to move – particularly at night – and is often linked with unpleasant sensations in the lower limbs.
It affects up to one in 20 adults in the UK – leading to severe sleep deprivation in many cases.
The study of almost 170,000 individuals found those with RLS (restless leg syndrome) were 2.7 times more likely to take their lives or self harm.
Corresponding author Professor Xiang Gao, an epidemiologist at Penn State University in the US, said: “It suggests restless legs syndrome isn’t just connected to physical conditions, but to mental health, as well.
“And, with RLS being under-diagnosed and suicide rates rising, this connection is going to be more and more important.
“Clinicians may want to be careful when they are screening patients both for RLS and suicide risk.”
In the US suicide rates have risen by up to 30 percent since the turn of the century. In the UK, it is the single biggest killer of men under the age of 45.
Prof Gao said: “Suicide is a global health concern and is associated with multiple risk factors, including male sex, family history of suicide, childhood adversity, alcohol abuse, psychiatric disorders and sleep problems.
“Given sleep disturbance and depression are highly concurrent in individuals with RLS, it is plausible part of the elevated overall mortality risk associated with RLS maybe driven by increased risk of death from suicide.”
Prof Gao and colleagues said RLS affects about five percent of the US population. It may be caused low levels of the feelgood brain chemical dopamine – which also controls movement.
Some studies have linked it to high blood pressure , heart attacks and increasing mortality rates, and others to depression and suicidal thoughts.
Prof Gao said: “I have wanted to explore a potential connection between RLS and suicide for more than 10 years.
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“But because both RLS and suicide rates are low from a data perspective, it was not possible.
“But, when I moved here to Penn State, I gained access to a data set with more than 200 million people, so it gave us power to finally test this hypothesis.”
His team compared health information on privately insured Americans between 2006 and 2014 – 24,179 of whom had been diagnosed with RLS and 145,194 who had not.
The study, published in JAMA Network Open, found the former group had a 270 percent higher chance of suicide or self harm.
Neither they nor the control set had any history of the behaviours before the tracking began.
The risk did not drop even after depression, sleep disorders and common chronic diseases such as diabetes were taken into account.
Co author Prof Muzi Na, an expert in health promotion and disease prevention at Penn State, added: “After controlling for these factors, we still did not see the association decrease, meaning RLS could still be an independent variable contributing to suicide and self harm.
“We still do not know the exact reason, but our results can help shape future research to learn more about the mechanism.”
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