Study: OCD Linked to Increased Risk of Death

Experts call for enhanced monitoring, preventative measures, and early response tactics.

A study from Sweden, recently published in The BMJ, suggests that individuals diagnosed with obsessive-compulsive disorder (OCD) might face a higher risk of mortality from natural as well as unnatural causes compared to those who do not have the disorder.

The researchers point out that many of the natural causes of death are preventable, suggesting that better surveillance, prevention, and early intervention strategies should be implemented to reduce the risk of fatal outcomes in people with OCD.

OCD is typically a long-term psychiatric disorder affecting about 2% of the population. It is characterized by intrusive thoughts, urges, or images that trigger high levels of anxiety and other distressing feelings – known as obsessions – that the person tries to neutralize by engaging in repetitive behaviors or rituals – known as compulsions.

OCD is also associated with academic underachievement, poor work prospects, alcohol and substance use disorders, and an increased risk of death.

Research Objectives and Methodology

Previous studies on specific causes of death in OCD have mainly focused on unnatural causes (eg, suicide), but little is known about specific natural causes.

To fill this knowledge gap, researchers set out to estimate the risk of all cause and cause specific death in people with OCD compared with matched unaffected people from the general population and with their unaffected siblings.

Using data from several Swedish population registers, they identified 61,378 people with OCD and 613,780 individuals without OCD matched (1:10) by sex, birth year, and county of residence, and a further sibling group of 34,085 people with OCD and 47,874 without OCD.

The average age at OCD diagnosis was 27 years and groups were monitored for an average of 8 years from January 1973 to December 2020.

Findings on Mortality Risks

Overall, people with OCD had a higher death rate than matched individuals without OCD (8.1 versus 5.1 per 1,000 person-years, respectively).

After adjusting for a range of potentially influential factors such as birth year, sex, county, migrant status, education, and family income, people with OCD had an 82% increased risk of death from any cause.

The excess risk of death was higher for both natural (31% increased risk) and, particularly, unnatural causes of death (a 3-fold increased risk).

Among the natural causes of death, people with OCD had increased risks due to 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%).

Among the unnatural causes, suicide showed the highest risk of death (a nearly fivefold increased risk), followed by accidents (a 92% increased risk).

Gender Differences and Study Limitations

The risk of all-cause death was similar in both women and men, although women with OCD had a higher relative risk of dying due to unnatural causes than men with OCD, likely due to the lower baseline risk among women in the general population, note the researchers.

In contrast, people with OCD had a 10% lower risk of death due to tumors (neoplasms).

This is an observational study, so can’t establish cause and the researchers point out that registry data only includes diagnoses made in specialist care. It’s also unclear whether the findings generalize to other settings with different populations, health systems, and medical practices.

Nevertheless, this was a large study based on high-quality national data, and the results remained largely unchanged after further adjustment for psychiatric conditions and family factors, suggesting that they withstand scrutiny.

As such, they conclude: “Non-communicable diseases and external causes of death, including suicides and accidents, were major contributors to the risk of mortality in people with OCD. Better surveillance, prevention, and early intervention strategies should be implemented to reduce the risk of fatal outcomes in people with OCD.”

Reference: “All cause and cause specific mortality in obsessive-compulsive disorder: nationwide matched cohort and sibling cohort study” by Lorena Fernández de la Cruz, Kayoko Isomura, Paul Lichtenstein, Henrik Larsson, Ralf Kuja-Halkola, Zheng Chang, Brian M D’Onofrio, Isabell Brikell, Christian Rück, Anna Sidorchuk and David Mataix-Cols, 17 January 2024, BMJ.
DOI: 10.1136/bmj-2023-077564

The study was funded by the Swedish Research Council for Health, Working Life and Welfare, Region Stockholm, and the Swedish Society of Medicine, Karolinska Institutet.