Network of positive affect and depression in older adults: Twin study

Higher levels of positive affect (PA) are consistently associated with lower depressive symptoms in older adults; however, the relative importance of specific PA components remain unclear. This study examined which discrete PA facets show the strongest associations with depressive symptoms and whether these associations reflect genetic or environmental influences using twin methodology and longitudinal network analysis.

Data were drawn from 540 older twins (mean age = 71 years, 65% female) participating in the Older Australian Twins Study across three waves spanning four years. PA was assessed using the Positive and Negative Affect Schedule (PANAS), and depressive symptoms were measured using the Geriatric Depression Scale (GDS-15). Additive genetic, common environmental, and unique environmental (ACE) models were applied to estimate variance components. Bayesian Gaussian Graphical Models were used to characterise affective networks, Directed Acyclic Graphs examined conditional directional associations, and hierarchical regression analyses tested longitudinal associations between baseline PA components and subsequent depressive symptoms.

ACE modelling indicated that overall PA was predominantly influenced by environmental factors (53.1%), whereas depressive symptoms showed a stronger genetic contribution (59.5%). Across twin pairs and timepoints, network analyses consistently identified enthusiasm as the most central PA component. Enthusiasm and feeling active showed the strongest negative associations with depressive symptoms (partial correlations ranging from -0.12 to -0.18). Longitudinally, enthusiasm showed stronger concurrent associations with depressive symptoms, whereas feeling active demonstrated more sustained associations over the four-year follow-up. These patterns were consistent across monozygotic and dizygotic twin pairs.

Specific PA states, particularly feeling enthusiastic and feeling active, show consistent associations with depressive symptoms in older adulthood and appear largely environmentally influenced. These findings highlight discrete emotional experiences that may be relevant targets for low-risk, non-pharmacological strategies aimed at supporting psychological well-being in aging populations, while complementing established approaches to depression prevention and treatment.