Stress disorders increase infection risk

A Swedish observational study has found that post-traumatic stress disorder (PTSD) and other stress-related disorders are associated with a subsequent risk of life-threatening infections such as meningitis and sepsis. The results published in The BMJ demonstrate that the risk of infection is particularly high in those diagnosed at a younger age and those with other psychiatric conditions.

The research team used Swedish population and health registers to compare infection rates in 144,919 patients diagnosed with a stress-related disorder with those of 184,612 unaffected full siblings. A further 1,449,190 unaffected individuals from the general population were also studied.

Stress-related disorders included PTSD, acute-stress reaction, adjustment disorder and other stress reactions. Infections included sepsis, endocarditis (infection of the inner lining of the heart) and meningitis or other central nervous system infections.

Participants were monitored for an average of eight years, with the average age at diagnosis being 37 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.

Stress-related disorders were 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 the presence of other psychiatric conditions, especially substance use disorders, were associated with further risk increases. Use of selective serotonin re-uptake inhibitors (SSRI) antidepressants in the first year after diagnosis appeared to have a protective effect.

In a similar study published earlier this year, the authors found a link between stress-related disorders and risk of cardiovascular disease. The researchers have called for increased awareness among health professionals caring for patients with stress-related disorders, especially those diagnosed at a younger age.

Although the precise mechanisms linking stress-related disorders to physical ill health are still unclear, Jonathan Bisson, Professor of Psychiatry at Cardiff University School of Medicine, explained that a range of biological, psychological and social factors are likely contributors.

Prof Bisson said that the Swedish study adds to other research supporting the existence of overlapping mechanistic pathways between mental and physical health. Prof Bisson believes a holistic approach to research and management of stress-related disorders, in partnership with patients and families, is likely the best way to help people with these conditions.

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