Neuroticism, conscientiousness, and in vivo Alzheimer pathologies measured by amyloid PET and MRI

Abstract

Aim It has been suggested that personality traits, particularly neuroticism and conscientiousness, are risk factors for Alzheimer's disease (AD) and related cognitive decline. However, the underlying pathological links between personality traits and AD‐related cognitive impairments remain unclear. Thus, the present study investigated associations of neuroticism and conscientiousness with in vivo cerebral amyloid‐beta (Aβ) burden, AD‐signature regional neurodegeneration, and white matter hyperintensities (WMH) in non‐demented middle‐ and old‐aged adults. Methods A total of 397 non‐demented participants underwent comprehensive clinical and neuropsychological assessments, 11C‐labeled Pittsburgh Compound B positron emission tomography, and magnetic resonance imaging. Additionally, the NEO Five‐Factor Inventory was administered to both the participants and their informants to measure neuroticism and conscientiousness. Results Neither neuroticism nor conscientiousness was associated with cerebral Aβ deposition or WMH. In contrast, higher neuroticism and lower conscientiousness, reported by informants in particular, were significantly associated with reduced AD‐signature region cortical thickness. In regards to the direct and indirect effect of each personality on AD‐signature region cortical thickness, only the direct effects were found, whereas indirect effects via Aβ deposition or WMH were not. Conclusion The present findings suggest that amyloid‐independent regional neurodegeneration might underlie relations of neuroticism and conscientiousness with AD.

Circadian rest‐activity rhythm and longitudinal brain changes underlying late‐life cognitive decline

“…All participants underwent MRI scans with fluid‐attenuated inversion recovery using the abovementioned PET‐MER scanner. We followed the validated automatic procedure previously reported 36,37 . Briefly, the procedure consisted of 11 steps: spatial coregistration of T1 and fluid‐attenuated inversion recovery (FLAIR) images, fusion of T1 and FLAIR images, T1 segmentation, attainment of transformation parameters, deformation and obtainment of the white matter mask, obtainment of FLAIR within the white matter mask, intensity normalization of the masked FLAIR, nomination of candidate WMH with a designated threshold, creation of a junction map, and elimination of the junction.…”

“…We followed the validated automatic procedure previously reported. 36,37 Briefly, the procedure consisted of 11 steps: spatial coregistration of T1 and fluid-attenuated inversion recovery (FLAIR) images, fusion of T1 and FLAIR images, T1 segmentation, attainment of transformation parameters, deformation and obtainment of the white matter mask, obtainment of FLAIR within the white matter mask, intensity normalization of the masked FLAIR, nomination of candidate WMH with a designated threshold, creation of a junction map, and elimination of the junction. Two modifications in the current processing procedure compared with the original study were as follows 37 : (i) an optimal threshold of 70 was applied because it was more suitable for current data compared with the threshold of 65 used in the original study; and (ii) we did not use diffusion-weighted imaging in the current automated procedure given that participants with acute cerebral infarcts were enrolled in the original study.…”

The more the neuroticism, the more the susceptibility to Alzheimer's disease. What inspiration can neuroticism provide?

“…Finally, for those with high levels of neuroticism, the following question may arise: “Are there any other ‘rescues’ in the absence of a specific effective intervention strategy for neuroticism?” Some studies have shown that neuroticism develops primarily early in life and is relatively stable in adulthood 18 . Indeed, besides neuroticism, three personality traits— conscientiousness, agreeableness, and openness—were negatively correlated with the deposition of Aβ and tau 2 . This suggested that even though some individuals may have high levels of neuroticism in general, we can take many strategies to make ourselves responsible, outgoing, and comfortable to counterac the extra risk of AD associated with neuroticism.…”

“…In other words, AD can induce changes in the personality, but little is known about whether personalities can affect the onset or development of AD. (2) The evaluation dimension can be reduced and this can enable specific focus on the problem. Neuroticism is a comprehensive indicator, which is related not only to pathological markers but also some hormones and submicroscopic molecules, such as glucocorticoids 16 (which may cause hippocampal neuron damage in AD patients), microtubule-associated tau protein (MAPT), and a common posttranscriptional messenger RNA modification N 6 -methyladenosine quantitative trait loci (m 6 A QTLs).…”

“…It seems that their brains are wired differently: they often have an active mind but unstable control of their emotions, which makes them more prone to negative emotions (such as sadness, depression, and anxiety or other mood disorders). 1 Exploration of the pathogenesis and treatment strategies of Alzheimer's Disease (AD) shows that there are remarkable similarities between neurotic and AD brains, such as a higher deposition of pathological markers (e.g., amyloid-beta [Aβ] and tau phosphorylation [Tau]), 2 more active inflammatory response, 3 and structural and functional changes 4 in specific cerebral regions. These similarities led us to hypothesize that neuroticism may be closely related to the onset of AD, and it could provide new insight to overcome some obstacles in traditional AD research.…”