PTSD linked to increased risk of Parkinson’s in meta-analysis

Among four studies reporting a risk ratio, odds higher with PTSD

Lindsey Shapiro, PhD avatar

by Lindsey Shapiro, PhD |

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A roll of the dice illustrates the risk of developing disease.

People with post-traumatic stress disorder (PTSD) were found to be at a higher risk of Parkinson’s disease or related neurodegenerative conditions, a small meta-analysis suggests.

“The small number of studies to date provide preliminary evidence of an association between mid- to late-life onset PTSD and subsequent development of [Parkinson’s] and related neurodegenerative synucleinopathies,” the researchers wrote in “Post-traumatic stress disorder and risk of degenerative synucleinopathies: systematic review and meta-analysis,” which was published in The American Journal of Geriatric Psychiatry.

More research is needed to understand this potential relationship, they said, noting such studies must include standardized neuropsychiatric assessments, more detailed clinical profiling, and longer-term follow-up.

Parkinson’s is a neurodegenerative disease marked by the toxic buildup in the brain of the alpha-synuclein protein.

Mental health conditions such as anxiety and depression are known to be early symptoms of Parkinson’s, emerging before its hallmark motor symptoms in many cases. Indeed, both depression and anxiety have been associated with an increased risk of Parkinson’s.

PTSD is a mental health condition where people who’ve had a a fear-inducing trauma continue to experience feelings of significant stress even when they’re no longer in danger. It’s highly prevalent in military veterans, potentially affecting more than 20%, but it also occurs in victims of abuse or those who’ve undergone physical, sexual, or emotional trauma.

Emerging evidence suggests a relationship between PTSD and the later emergence of Parkinson’s or other neurodegenerative diseases.

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Increased risk of Parkinson’s, neurodegenerative disorders with PTSD

Veterans with PTSD have been previously found to be at an increased risk of developing rapid eye movement (REM) sleep behavior disorder, a common early Parkinson’s symptom.

More research is needed to better understand the potential relationship between PTSD and Parkinson’s, however, in order to understand if it’s a risk factor that can be modified to avoid the disease, said the researchers who conducted a meta-analysis of previously published studies related to PTSD and Parkinson’s or other related diseases marked by alpha-synuclein buildup, such as dementia with Lewy bodies (DLB) — collectively referred to as degenerative synucleinopathies.

They identified six studies of 1,747,378 people. One had two separate arms for a total of seven data points. Four analyses looked at Parkinson’s disease and three looked at DLB. Each study had a different design and included different metrics for diagnosing PTSD, follow-up lengths, sex, race, and age distributions.

Six analyses found a relationship between PTSD and some form of degenerative synucleinopathy. Among the four studies that reported a risk ratio, the odds of developing one of these neurodegenerative conditions was 1.35 to 3.46 times higher among those with PTSD than those without it.

A final meta-analysis involving those four studies revealed that people with PTSD were at a 1.88 times higher risk of developing a degenerative synucleinopathy than those without PTSD, although there was significant variability across the studies.

“Taken together, the limited [existing] literature indicates a need for further research on mid- to late-life PTSD as a risk factor or prodromal [early] manifestation of degenerative synucleinopathies,” the researchers wrote, noting that “several questions … remain unanswered by this review.” Particularly, it isn’t clear if other conditions that often coexist with PTSD, such as traumatic brain injury or insomnia, might confound the findings.

The role of other factors, such as cause of PTSD, age of its onset, and its specific symptoms also warrant further examination, the researchers said.