Depressive symptoms in later life: differential impact of social support and motivational processes on depression in individuals with and without cognitive impairment.

This study investigates the role of a motivational process based on a composite of four subcomponents (self-efficacy, decision regulation, activation regulation and motivation regulation), as a mediator of the relationship between social support and depression assessed with the Geriatric Depression Scale in cognitively impaired and unimpaired individuals. Participants were 229 adults with a mean age of 74 years (range: 52-94 years). The sample comprised 64 participants diagnosed with mild cognitive impairment (MCI), 47 participants diagnosed with early-stage Alzheimer's disease (AD), and a group of 118 participants without any cognitive impairment. In this cross-sectional study, bivariate correlations and linear regression models were used to assess the association between the predictor variables and depression. Linear regression models were controlled for age, gender, education, cognitive status, cognitive impairment and activities. In the total sample, social support (β = -0.15, p < 0.05) and motivational processes (β = -0.41, p < 0.001) were significantly associated with depression; the impact of social support was mediated by motivational processes. While motivational processes were associated with depression in all three groups (no impairment: β = -0.61, p < 0.001; MCI: β = -0.28, p < 0.05; early AD: β = -0.30, p < 0.06), social support lost significance (no impairment: β = -0.36, p < 0.001; MCI: β = 0.07, p = 0.59; early AD: β = -0.08, p = 0.62). Based on these findings, it can be argued that the impact of social support on depressive symptoms is attenuated by cerebral deterioration in cognitively impaired individuals, while motivational processes remain relevant.