Patients with OCD are 10 times more likely to commit suicide, contrary to what was previously thought. In a new study from Karolinska Institutet published in the journal Molecular Psychiatry, is also shown that the main predictor of suicide in OCD patients is a previous suicide attempt, which offers opportunities for prevention.

Suicide is a major public health problem that leads to an estimated 800,000 deaths worldwide each year. People with mental health conditions are at higher risk to die by suicide, and about 90 percent of those who die by suicide are considered to suffer from a mental disorder.

However, little attention has been paid to the risk of suicide among people suffering from obsessive-compulsive disorder (OCD), one of the most common psychiatric disorders. OCD has a lifetime prevalence of about two per cent in the general population, generally runs a chronic course, and is often associated with a significantly reduced quality of life. The risk of suicide in OCD has traditionally been considered low.

In order to estimate the risk of suicide among people affected by OCD and identify risk and protective factors associated with suicidal behavior in this group, the researchers analyzed data from the Swedish national registers, spanning over 40 years.

They identified 36 788 OCD patients in the Swedish National Patient Register between 1969 and 2013, of whom 545 had died by suicide and 4297 had attempted suicide. The risk of death by suicide was approximately ten times higher, and the risk of attempted suicide five times higher than that of the general population. After adjustment for other psychiatric disorders, the risk was reduced, but remained substantial.

- Within the OCD cohort, a previous suicide attempt was the strongest predictor of death by suicide. Having a personality disorder or a substance use disorder also increased the risk. In contrast, being a woman, higher socioeconomic status, and having an anxiety disorder were protective factors, says Lorena Fernández de la Cruz, an Assistant Professor at the Department of Clinical Neuroscience.

- The researchers concluded that patients with OCD are at significant risk of suicide, even in the absence of other psychiatric conditions, which clinicians should be aware of. Suicide risk must be closely monitored in these patients, especially in those who have previously attempted suicide. These results are a first step towards the design of preventive strategies aimed at preventing fatal consequences in patients with OCD.