People with Tourette's disorder or chronic tic disorder are over four times more likely to die by suicide than the general population, according to a new study in Biological Psychiatry. Dr. David Mataix-Cols of Karolinska Institute, Sweden, led the study of the largest group of patients with tic disorders in the world.
The study sample included 7,736 patients from the Swedish National Patient Register diagnosed with tic disorders over four decades. Compared with 77,360 people from the general population, the increased risk remained even after taking other psychiatric comorbidities into account, showing that tic disorders are associated with an increased risk of suicide in their own right.
"The results highlight an under-recognized mental health need in people with Tourette's and chronic tic disorders," said first author Dr. Lorena Fernández de la Cruz, also of Karolinska Institute, referring to the scarce attention that suicide in tic disorders has received despite the substantial link between psychiatric illness and death by suicide. The authors hope the alarming risk found in the disorder will contribute to the clinical management of these patients.
Tic disorders typically emerge around 4 to 6 years old and often resolve in young adulthood. But for about 20 percent of patients, debilitating tics persist into adulthood. In the study, Fernández de la Cruz and colleagues found that a persistent diagnosis of a tic disorder into adulthood was the strongest predictor of suicide risk. A previous suicide attempt was also a strong predictor of death by suicide, and patients with tic disorders were nearly four times more likely to attempt suicide than people in the comparison group.
Although tic disorders affect more boys than girls, the risk of suicide was the same for both sexes. The researchers also assessed the impact on risk of other psychiatric disorders that commonly coincide with tic disorders, and found that comorbid personality disorders increased the risk of suicide by nearly threefold.
"The medical risks of tic spectrum disorders have been downplayed in the media, where individuals with tics may be portrayed in humorous ways. However, suicide is no laughing matter and the study by Fernández de la Cruz is a wake-up call for many about the potential seriousness of tic spectrum disorders," said Dr. John Krystal, Editor of Biological Psychiatry.
"Suicidal behavior should be carefully monitored long-term in these patients," said Fernández de la Cruz. The predictors that emerged in the study will help clinicians identify patients most in need of attention. Fernández de la Cruz added that the results are a first step toward the design of strategies aimed at preventing fatal consequences in patients with Tourette's and chronic tic disorders.
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Lorena Fernández de la Cruz et al. Suicide in Tourette's and Chronic Tic Disorders, Biological Psychiatry (2016). DOI: 10.1016/j.biopsych.2016.08.023