As dementia is expected to increase dramatically with global aging, risk and protective factors are being studied. Extrinsic risk factors include lower educational level, vascular risk factors, and head trauma. Intrinsic factors are mainly family history and genetic disorders. Another intrinsic factor recently studied is personality. One element of personality is termed dispositional traits. They may influence the risk of dementia by affecting behavior, lifestyle, or reactions to stress. Studies show that neuroticism is associated with cognitive decline and dementia. Other risk factors are longstanding distress and psychosocial stressors in midlife.
A new study, published in Neurology, sheds more light on these issues. It involved 153 women with a 38-year followup. There is a neuroticism scale that assesses emotional reactivity, anxiety, psychosomatic concerns, ego-strength, and guilt proneness. The flip side is the extraversion scale, which assesses sociability and positive affect. They found that the combination of low extraversion / high neuroticism had the highest risk of Alzheimer’s, whereas the combination of low neuroticism / high extraversion had a lower risk.
Possible explanations: People with low neuroticism may have a healthier lifestyle and less inflammatory risk profiles; high levels of glucocorticoid (stress) hormones may cause damage to areas of the brain important in learning, cognition, and memory; and low neuroticism has been found to be associated with higher levels of a beneficial compound termed serum brain-derived neurotrophic factor.
Dr. Jack Florin, MD