Is PTSD a Risk Factor for Parkinson’s Disease?
—Using data from the Veterans Health Administration, investigators conducted a retrospective analysis to examine the relationship between post-traumatic stress disorder and Parkinson’s disease.
Individuals with post-traumatic stress disorder (PTSD) face a higher risk of developing Parkinson’s disease, according to a nested case-control study using data from the Veterans Health Administration and Medicare.1
As with most diseases, knowing the risk factors for the development of Parkinson’s disease might help with prevention and better treatments. Stress is one of those possible risk factors.1 Several past studies have demonstrated associations between PTSD and Parkinson’s disease, with an increased risk of Parkinson’s disease after prior PTSD.2,3
The authors of a new report note that prior studies were limited by using ICD codes to assess Parkinson’s disease, and sought to build upon this evidence by examining a cohort of US military veterans with a validated diagnosis of Parkinson’s Disease in their medical records. The investigators found that only 39% of patients with an ICD code for Parkinson’s disease had a validated diagnosis.
Frances M. Weaver, PhD, of the Center of Innovation for Complex Chronic Healthcare, Edward Hines Jr. VA Hospital, Hines, Illinois, and colleagues, reported their results in the Journal of Parkinson’s Disease.1
Unveiling the link between PTSD and Parkinson’s
The study included 158,122 veterans stationed at either Camp Lejeune in North Carolina or Camp Pendleton in California between 1975 and 1985. PTSD was defined as ≥ 2 visits at least 3 months apart with a documented diagnosis by ICD code. Veterans were included if they had Parkinson’s disease based on ≥ 1 ICD code and confirmed by symptoms and medication for Parkinson’s disease documented in the electronic medical record (EMR).1 Smoking history was also included. The authors matched each veteran with 10 controls based on demographic factors and rank.1
Of the veterans with Parkinson’s disease (n=430), 15.1% had a history of PTSD vs 12.6% of matched controls (P = .15). Additionally, the patients with Parkinson’s disease were less likely to have ever smoked (38.1% vs 47.0%, P = .0005). After adjustment for which camp they had lived in, the risk of Parkinson’s disease overall was significantly higher in veterans with a history of PTSD (OR 1.34, 95% CI 1.15-1.57). This risk did not change with a history of smoking.
For veterans who sought medical care for any reason before being diagnosed with Parkinson’s disease, there was a stronger association with PTSD (OR 1.49, 95% CI 1.29–1.72. When the diagnosis of PTSD occurred before the diagnosis of Parkinson’s disease, the odds of developing Parkinson’s disease were 1.53 times greater than not having a previous PTSD diagnosis (P < .0001).
Clinical implications: better monitoring of patients with PTSD
In an interview with , Dr. Weaver discussed the clinical implications of their study. She said, “The findings of this study suggest that PTSD may be a significant risk factor for developing Parkinson's disease among veterans. Clinically, this highlights the importance of monitoring individuals with PTSD for early signs of Parkinson's disease, particularly within the veteran population.”
“Given that stress-related mechanisms, such as inflammation and neuronal changes, are implicated in both conditions,” she continued, “integrating stress management and targeted therapies for PTSD might help mitigate the risk of Parkinson's disease. Clinicians should consider routine neurological evaluations and possibly early interventions for veterans with a history of PTSD to delay or prevent the onset of Parkinson's disease.”
She added, “One of the key strengths of this study is the rigorous case-finding method used to validate Parkinson's disease diagnoses, which enhances the reliability of the association observed between PTSD and Parkinson's disease. This study adds to the growing body of evidence that stress-related disorders like PTSD can have long-term neurodegenerative consequences. For veterans and their healthcare providers, this underscores the need for heightened awareness and proactive management of PTSD, not only for mental health but also for its potential neurological impacts.”
Looking ahead
Regarding future studies, Dr. Weaver told , that they “should focus on exploring the underlying biological mechanisms linking PTSD and Parkinson’s disease, particularly the role of chronic stress and inflammation. Longitudinal studies involving diverse populations beyond veterans would help establish the generalizability of these findings. Additionally, research could investigate the effectiveness of early stress reduction and PTSD treatments in lowering Parkinson’s disease risk. It would also be beneficial to examine the impact of co-occurring conditions, such as traumatic brain injury, on the relationship between PTSD and Parkinson’s disease to develop more comprehensive risk profiles.”
The main limitation of this study noted by the authors is that it was difficult to assess the temporal association between PTSD and Parkinson’s disease, as the diagnosis of PTSD in the EMR was probably when the provider found out about the diagnosis vs when the PTSD actually occurred. In addition, there may have been other factors that were not accounted for that could have affected the relationship between PTSD and Parkinson’s disease, such as a prior PTSD diagnosis and/or a traumatic brain injury.1
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