TALLAHASSEE, Fla. — People with a particular personality type may be more prone to developing Parkinson’s disease, a recent study reveals. Researchers from the Florida State University College of Medicine discovered a link between neuroticism, a personality trait that causes unpleasant emotions such as rage, irritability, anxiety, self-consciousness, and even emotional instability, and the progressive neurological disorder.
Antonio Terracciano, a professor in the Department of Geriatrics at FSU, led the research. He and his colleagues discovered that participants in the study group who scored in the highest 25 percent for neuroticism had an 80 percent higher probability of developing Parkinson’s disease than those who scored below.
“Some clinicians think that the anxiety and depression is just the result of Parkinson’s,” Terracciano says in a university release. “However, our findings suggest that some emotional vulnerability is present early in life, years before the development of Parkinson’s disease.”
Women and men, as well as those from different socioeconomic backgrounds, had similar results. Moreover, the relationship remained steady in these groups after the team factored in characteristics and other risk factors, including physical activity, smoking, anxiety, and depression. The pattern continued to show up even after researchers excluded disease cases coming within the initial five-year follow-up period.
Three other studies with reduced sample sizes have reported results that are comparable to this study. According to Terracciano, the findings give a “pretty robust and replicable” evaluation of the relationship between neuroticism and Parkinson’s disease.
“It kind of gives you a better understanding of the risk factors for the disease and what could be a contributing cause,” the study author explains. “This is one of many [factors], but the evidence is convincing.”
How does neuroticism impact the mind?
Currently the second-highest prevalent neurological illness after Alzheimer’s, Parkinson’s disease affects approximately six million individuals worldwide. That’s equivalent to one percent of all elderly individuals. Although the causes of Parkinson’s disease remains unclear, experts think both hereditary and environmental variables have a role in its development.
Neuroticism is among the five key character qualities scientists list in the “Big Five,” the personality model that includes five major character traits. Individual variations in the likelihood of having unpleasant emotions, sensitivity to stress, difficulty to resist impulses, and self-consciousness are all factors in a person’s level of neuroticism. It is among the most common psychological dispositions scientists examine because of its significance to normal and pathological emotional processing.
Previous research has linked neuroticism to emotional abnormalities, and even Alzheimer’s disease, but there is less research on its potential association with Parkinson’s disease.
“Individuals who score high in neuroticism are at higher risk for poor health outcomes across the lifespan, particularly in the domain of mental health and neurodegenerative diseases, including Alzheimer’s disease and related dementias,” Terracciano reports.
Mental health plays a key role in Parkinson’s disease
Terracciano’s investigation used data coming from a substantial study conducted by the UK Biobank. The national study involved over 500,000 people between 40 and 69 years-old selected between 2006 and 2010. Researchers gathered data over the span of 12 years before assessing each person’s level of neuroticism. Prior to 2018, there were 1,142 confirmed occurrences of Parkinson’s disease according to on UK National Health Service online health data or death certificates.
“Anxiety and depression are comorbid with Parkinson’s disease,” Terracciano continues. “Many people with Parkinson’s tend to be anxious or tend to get depressed. Part of that could be due to the disease and how it alters the brain and can have an influence on emotions. Part could be a psychological reaction of having a diagnosis of the disease.”
Parkinson’s is an indelible brain disease which sees patients deal with a gradual decrease in cognitive and physical abilities. Dopamine levels drop due to nerve cell destruction during the development of the disease. Dopamine is a “feel-good” hormone that regulates bodily motions as well as reward, drive, memory, and attentiveness. Reduced levels cause symptoms such as shakes, sluggish movement, rigidity, and loss of coordination.
This study is published in the journal Movement Disorders.