OCD Linked to Increased Risk of Death from Natural and Unnatural Causes

Lorena Fernández de la Cruz, PhD

Credit: Karolinska Institutet

Individuals with obsessive-compulsive disorder (OCD) are linked to an increased risk of death, according to a new study.¹

Previous research evaluating the link between OCD and the risk of death focused primarily on unnatural deaths, such as suicide or accidents.² However, many individuals with OCD are susceptible to natural deaths.

Investigators of the new study, led by Lorena Fernández de la Cruz, PhD, from the Karolinska Institutet in Stockholm, Sweden, sought to estimate the risk of all-cause and cause-specific mortality in people with OCD compared to unaffected people from the general population and unaffected siblings. They found individuals with OCD have an 82% increased risk of death.

“We report, for the first time, on the specific causes of death in people with OCD, compared with unaffected people,” investigators wrote. “Most of these causes can be classified as noncommunicable diseases (for example, cardiovascular diseases, diabetes, chronic respiratory diseases, mental disorders, neurological disorders), which are often related to potentially modifiable behavioral risk factors.”

Conflicting data exists on the risk of mortality among people with OCD. A 2013 US study using data from the Epidemiologic Catchment Area Program reported people with OCD had a 22% lower risk of death compared with unaffected people. Yet, another study based in Denmark found the opposite: the risk of mortality was approximately twofold greater in people with OCT than in unaffected people.

Fernández de la Cruz and colleagues obtained data from several Swedish population registers over a 48-year period lasting from 1973 - 2020, identifying 61,378 people with OCD and 613,780 people without OCD. Individuals with OCD and controls were matched 1:10 by sex, birth year, and country of residence. They also had a sibling group and compared 34,085 individuals with OCD and 47,874 without OCD. The average age at OCD diagnosis was 27 years.

The team monitored the groups for a mean of 8 years from January 1973 – December 2020. They observed people with OCD had a greater rate of death than individuals without OCD as 4787 people with OCD and 30,619 unaffected people died during the study period (crude mortality rate 8.1 vs. 5.1 per 1,000 person-years, respectively).

For individuals who died of mental and behavioral disorders—both in the OCD cohort and the unaffected cohort—the most common specific causes of death were unspecified dementia, vascular dementia, and mental and behavioral disorders due to alcohol. Additionally, the investigators observed women and men with OCD experienced a similar increase in risk of all-cause mortality.

More deaths in the OCD cohort than the unaffected cohort occurred due to the following natural causes: respiratory system diseases (73%), mental and behavioral disorders (58%), diseases of the genitourinary system (55%), endocrine, nutritional, and metabolic diseases (47%), diseases of the circulatory system (33%), nervous system (21%), and digestive system (20%). As for the natural death of neoplasms, the rate was lower in the OCD cohort than in the unaffected cohort. For unnatural causes of death, suicide had the highest hazard ratio, followed by accidents.

Moreover, Cox proportional hazards models adjusted for birth year, sex, county, migrant status, and sociodemographic variables (latest recorded education, civil status, family income), individuals with OCD have an increased risk of all-cause mortality (hazard ratio [HR], 1.82; 95% confidence interval [CI], 1.76 – 1.89) and mortality due to natural causes (HR, 1.31; 95% CI, 1.27 – 1.37) and unnatural causes (HR, 3.30; 95% CI, 3.05 – 3.57).

“An unexpected finding in our study was that the risk of death due to neoplasms was 13% lower in the OCD cohort, compared with the matched unaffected people,” investigators wrote. “A paradoxical observation has been previously described by which people with psychiatric conditions, including those with OCD, have lower or similar cancer incidence compared with unaffected people but higher cancer related mortality rates, likely attributed to lower detection rates in the psychiatric groups, which we did not find in our study.”

Of all deaths, dying due to unnatural causes had the greatest risk estimates due to the nearly fivefold increased risk of suicide (for neuro-development disorders: HR, 4.43; 95% CI, 3.96 - 4.96).

The investigators wrote how the findings should “settle previous claims” that individuals with OCD have a low risk of suicide.

The study had multiple limitations, such as only including participants from specialist care, the frequency of some specific causes of death being relatively low, and the analysis adjusting for the last registered level of education, civil status, family income—such characteristics could have served as mediators, not comorbidities. Moreover, the team mentioned the limitation of having a lack of access to variables known to be linked to several non-communicable diseases such as a sedentary lifestyle, unhealthy diet, and smoking.

“Better surveillance, prevention, and early intervention strategies should be implemented to reduce the risk of fatal outcomes in people with OCD,” investigators concluded.

References

1. Obsessive-Compulsive Disorder Linked to Heightened Risk of Death. EurekAlert! January 17, 2024. https://www.eurekalert.org/news-releases/1031524. Accessed January 18, 2024.
2. Fernández de la Cruz L, Isomura K, Lichtenstein P, et al. All cause and cause specific mortality in obsessive-compulsive disorder: nationwide matched cohort and sibling cohort study. BMJ. 2024;384:e077564. Published 2024 Jan 17. doi:10.1136/bmj-2023-077564