Post-traumatic stress disorder (PTSD) and other stress-related disorders are associated with a subsequent greater risk of life-threatening infections such as meningitis and sepsis, suggests the findings of a large Swedish study* published in The BMJ.
Patients diagnosed with stress-related conditions at a young age and those with other psychiatric conditions appear to be at the greatest risk, according to the findings.
The study used data from Swedish population and health registers to assess whether severe psychiatric reactions to trauma and other adversities are associated with subsequent risk of life-threatening infections. Infection rates for 144,919 patients diagnosed with a stress-related disorder (PTSD, acute stress reaction, adjustment disorder, and other stress reactions) were compared with those in 184,612 unaffected full siblings of these patients and a further 1,449,190 unaffected individuals from the general population. Average age at diagnosis of a stress-related disorder was 37 years and participants were monitored for an average of eight years.
During follow-up, new cases of life-threatening infections per 1000 person years was 2.9 in patients with a stress-related disorder compared with 1.7 in unaffected siblings and 1.3 in unaffected individuals from the general population. Infections included sepsis, endocarditis (infection of the inner lining of the heart), and meningitis or other central nervous system infections.
After controlling for family history and other physical or psychiatric conditions, stress-related disorders were found to be associated with all studied infections, with the highest relative risks found for meningitis (63% increased risk) and endocarditis (57% increased risk) compared with unaffected siblings.
Younger age at diagnosis and presence of other psychiatric conditions, especially substance use disorders, were associated with further risk increases, whereas use of selective serotonin reuptake inhibitors (SSRI) antidepressants in the first year after diagnosis appeared to have a protective effect.
Although the study was observational and the absolute risk of life-threatening infections found remained low, the researchers said it was important that health professionals were made more aware of the potential associated risk because of the high mortality rate associated with the infections if they occurred.
They also called for further studies to better understand the roles of lifestyle factors as well as treatments for stress related disorders in reducing the excess risk of life-threatening infections.
*Song H, Fall K, Fang F, et al. Stress related disorders and subsequent risk of life threatening infections: population based sibling controlled cohort study. BMJ, 2019; 367:l5784