Stress may damage your immune response long term

Adapted from: Stress related disorders and physical health.  Song H. et al. BMJ 26 Oct 19.

This Swedish study of almost 145,000 brothers and sisters showed that any sort of anxiety or stress disorder was associated with an increased risk of life threatening infections, even when familial background, physical and psychiatric problems were adjusted for.

The study went on between 1987 and 2013. The stresses included post traumatic stress disorder, acute stress reaction, adjustment disorder and others. The patients were matched with healthy siblings when possible or matched comparative children from the general population.  They then looked for diagnosis of severe infection in the coming years such as sepsis, endocarditis, meningitis and other infections.

Severe infection rates per 1,000 person years were 2.9 for the stressed person, 1.7 for the healthy sibling, and 1.3 for the matched person in the general population.

They found that the effects were worse the earlier the age the diagnosis of the stress occurred.

Treatment with serotonin re-uptake inhibitors for PTSD seemed to reduce the negative effects on the immune system when given within a year of the stress diagnosis.

This research builds on information that PTSD produces more gastrointestinal, skin, musculoskeletal, neurological, heart and lung disorders.  Cardiac mortality has been found to be raised 27% and autoimmune disorder by 46%.

Why this happens could be due to the interplay between biological, psychological and social factors. Increased inflammatory response is considered by Song and colleagues to be a likely mechanism. Increased levels of interleukin 6, interleukin 1 beta, tumour necrosis factor alpha and interferon gamma have been found in those with PTSD.

PTSD has a heritability factor of 5-20% which is similar to what is found in families with depression.  It is likely to be polygenic.

Talking based therapies are generally even better for PTSD than drugs, so earlier intervention may have long term benefits not just on mental health, but physical health as well.

BMJ 2019;367:16036