Does trauma break your heart? A meta-analysis of cardiac disease and PTSD.

Despite the hype from ‘trauma creators,’ a new meta-analysis finds not much to worry about.

CATEGORY: CONTROL OF LANGUAGE AND IDEAS

First-author Arum Lim

Source: Journal of Psychiatric Research
Read time: 2.3 minutes
 
This Happened
A meta-analysis was published examining the possibility of a causal relationship between posttraumatic stress disorder (PTSD) and cardiovascular disease (CVD).
 
Who Did This?
Arum Lim is a PhD student in the Johns Hopkins School of Nursing. This is her first publication as first-author and her only one on trauma.
 
The Premise
Many cross-sectional studies have found a statistically-significant association between PTSD and CVD. Nearly all of them inferred that PTSD caused CVD, thus purposefully creating a sense of crisis in the public. But the causal relationship has always been inferred and is factually unclear.

This review took a relatively unusual approach for directly examining causality rather than assuming it existed.

​Lim and colleagues gathered all studies that measured at least one genetic factor in both PTSD and CVD (8 studies) or CVD-related factors (e.g., coronary artery disease, hypertension) (15 studies). The types of genetic factors ranged from genome-wide association studies, single-gene association studies, polygenic risk scores, DNA methylation, and telomere length.

The result was that authors found the usual cross-sectional association between PTSD and CVD, but, when more specifically analyzing for causation the authors concluded woefully “Evidence of a causal relationship between the two diseases was insufficient.”
 
Analysis
It cannot be overstated that the striking anomaly of this review is the authors’ attempt to find a causal relationship, as opposed to the enormity of studies that found cross-sectional associations, assumed it was causal, and called it a day. For those wishing to perpetuate the sense of crisis, this study might be an example of the old maxim for researchers who want to keep getting their shaky propositions funded: Don’t test things for which you don’t want to know the answers.
 
While this was a noteworthy effort, it was not, however, the best type of evidence that could test causality because the studies encompassed in this literature review were all cross-sectional. Their statistical technique inferred causality based on software modeling.
The best type of evidence to prove causality comes from pretrauma prospective studies in which PTSD and the biological variables are assessed prior to trauma exposure and a second time following trauma exposure. There is only one known pretrauma prospective study involving a cardiac factor [1]. That study (conducted in my lab) failed to find a causal relation between development of PTSD and heart rate variability in young children.
 
So, if there is an association but not a causal relationship, why is there an association? The authors dodged this question, instead doubling down in science-speak and suggesting that “complex networks are involved” and implying that the association still must be causal.
There are two alternative possible explanations. One is that the association finding is spurious (and tiny). A meta-analysis is only as good as the original studies. If the original studies were poor quality samples of convenience, a meta-analysis cannot improve upon that. Garbage in, garbage out. Another is that various profiles of genetic susceptibility to develop PTSD also lead to unhealthy lifestyles that sometimes lead to CVD.
 
Why Is This Happening?
For several decades, PTSD researchers have claimed that psychological trauma causes permanent damage to brains and bodily organs. Many researchers working in this area are deeply committed to the trauma-to-illness hypothesis, both intellectually and emotionally. They are the ‘trauma creators,’ fabricating a false worldview that trauma is the source of nearly all suffering. This commitment may shape how evidence is interpreted and which questions are prioritized. Institutional incentives, including funding priorities and publication trends, may reinforce a narrower focus and limit theoretical diversity. As a result, literature reviews that outright question the trauma-to-illness link are rare. 


References
[1] Mikolajewski AJ, Scheeringa MS (2018). Examining the prospective relationship between pre-disaster respiratory sinus arrhythmia and post-disaster posttraumatic stress disorder symptoms in children. Journal of Abnormal Child Psychology, Vol 46(7), Oct, 2018 pp. 1535-1545, DOI: 10.1007/s10802-017-0396-0.