The shared and unique genetic relationship between mental well-being, depression and anxiety symptoms and cognitive function in healthy twins

ABSTRACT

Alterations to cognitive function are often reported with depression and anxiety symptoms, yet few studies have examined the same associations with mental well-being. This study examined the association between mental well-being, depression and anxiety symptoms and cognitive function in 1502 healthy adult monozygotic (MZ) and dizygotic (DZ) twins, and the shared/unique contribution of genetic (G) and environmental (E) variance. Using linear mixed models, mental well-being was positively associated (p < .01) with sustained attention (β = 0.127), inhibition (β = 0.096), cognitive flexibility (β = 0.149), motor coordination (β = 0.114) and working memory (β = 0.156), whereas depression and anxiety symptoms were associated (p < .01) with poorer sustained attention (β = −0.134), inhibition (β = −0.139), cognitive flexibility (β = −0.116) and executive function (β = −0.139). Bivariate twin modelling showed well-being shared a small environmental correlation with motor coordination and a small genetic correlation with working memory. Trivariate twin modelling showed well-being shared a small genetic correlation with inhibition, whereas depression and anxiety symptoms shared a small environmental correlation with inhibition. The remaining variance was mostly driven by unique G and/or E variance. Overall, well-being and depression and anxiety symptoms show both independent and shared relationships with cognitive functions but this is largely attributable to unique G or E variance and small shared G/E variance between pairs of variables.

KEYWORDS:

• Well-being
• mental health
• twins
• attention
• inhibition
• executive function

Acknowledgements

LMW was the principal investigator of the project, PRS as a co-investigator, RC as a co-investigator, JMG as an ARC Linkage APDI post-doctoral fellow and Brain Resource Ltd as the industry partner. KMR is a Ph.D. student. KLOB is a Ph.D. student also working on the twin project.

Disclosure statement

KMR, KLOB, PRS and CRC have no conflicts of interest to report. AWF Harris has consulted for Lundbeck Australia and received fees for lectures from Janssen-Cilag and Lundbeck Australia. He has been an investigator on industry sponsored trials by Janssen-Cilag and Brain Resource Ltd. LMW has previously held stock options in BR and has received fees from BR for consultancies unrelated to this study. JMG has previously received consultancy fees from BR unrelated to this study and is a stockholder in Freedomsway Corp. Pte Ltd.

Additional information

Funding

This project was supported by an Australian Research Council (ARC) (Linkage grant LP0883621) with Brain Resource Ltd as industry partner. It was facilitated through access to the Australian Twin Registry, a national resource supported by a National Health & Medical Research Council (NHMRC) (Enabling grant 628911). KMR’s work was supported by a NHMRC Postgraduate Public Health Scholarship 1055839. JMG is supported by a NHMRC Career Development Fellowship 1062495. PRS is supported by NHMRC Program Grant 1037196.