The study used both Genomic Structure Equation Modeling and a twin/adoptive sample to explore the association between internalizing factors based on diagnoses (e.g., major depressive disorder; generalized anxiety disorder) and those based on self-reported measures of associated traits (e.g., neuroticism, worry). Results from both methods indicated the two factors were highly, but not perfectly, genetically correlated (genetic correlation = .76 to .79). Our findings are consistent with current frameworks of psychopathology, though they suggest there are some unique genetic influences captured by internalizing diagnosis compared to trait measures.
(Journal of Psychopathology and Clinical Science, 2024)
We used latent growth models to estimate changes in memory and executive function abilities across 3 assessments (mean age 56 to 68) in the VETSA sample. Alzheimer's disease polygenic scores predicted changes in both cognitive abilities, though associations with executive function were explained primarily by the APOE region.
(Journal of the International Neuropsychological Society, 2023)
We leveraged the twin/adoptive design of CATSLife to examine the heritability of executive function (EF) and its genetic overlap with intelligence in adults. Results suggest intelligence is more strongly genetically correlated with Upadating-specific abilities (rg = .69) than Common EF abilities (rg = .44). Dominance genetic influences may also mask the contribution of shared environmental influences on EF (but not intelligence) in adults.
Ìý
(Journal of Experimental Psychology: General, 2022)
This study compared participant-rated and informant-rated measures of subjective cognitive decline to participants' actual cognitive changes in episodic memory and executive function across 10-12 years in midlife (mean age 56, 62, and 68). Participant-reported decline was only modestly associated with objective decline for memory (β= –0.23) and executive function (β= –0.19), with ratings more strongly associated with concurrent depression and anxiety symptoms (β= 0.44). Results were similar for informant measures (though their ratings were less associated with participants' mood), suggesting that ratings of subjective cognitive decline capture only a small portion of variance in actual cognitive changes across middle age.
Ìý
(Journal of Alzheimer's Disease, 2021)
Using genomic SEM, we evaluated the genetic factor structure of two impulsivity questionnaires and their associations with internalizing psychopathology and delay discounting based on GWAS summary statistics. A five-factor model of impulsivity best fit the data, with the two urgency subscales most strongly relating to internalizing psychopathology, and all five facets of impulsivity genetically distinct from delay discounting. Findings support impulsivity as a multi-faceted construct with differential relevance to mental health.
(Psychological Science, 2020)
This twin study examined the extent to which internalizing and externalizing factors (based on diagnostic interviews) in midlife (age 41) predicted similar factors (based on self-reported measures) 15 to 21 years later. Internalizing psychopathology at age 41 was correlated with latent factors capturing anxiety, depression, and/or post-traumatic stress symptoms at ages 56 (r = 0.51) and 62 (r = 0.43) while Externalizing psychopathology at age 41 was correlated r = 0.67 with a latent factor capturing aggression, tobacco use, and alcohol use at age 56. Stability of both factors was driven by genetic influences, demonstrating the considerable stability of internalizing and externalizing psychopathology symptoms across middle age.
Ìý
(Psychological Medicine, 2019)
This twin study investigated the longitudinal stability of genetic and environmental influences on executive function across two waves of the Vietnam Era Twin Study of Aging (mean age 56 and 62). Despite substantial mean-level performance decline in common executive function ability (based on 7 neuropsychological tests at each wave), phenotypic, genetic, and environmental correlations were nearly 1.0 for both common executive function and working memory-specific latent factors across the two waves. These results suggest that there is substantial decline in executive function abilities across middle age but that individual differences are almost perfectly stable.
