Aging perceptions and self-efficacy mediate the association between personality traits and depressive symptoms in older adults.

OBJECTIVE: Personality traits have been shown to be predictors of depressive symptoms in late life. Thus, we examined whether other more modifiable sources of individual differences such as self-efficacy and self-perceptions of aging would mediate the association between personality traits and depressive symptoms in older adults. METHOD: Data were obtained from 3,507 older adult participants who took part in the 2012 Health and Retirement Study. The "Big Five" personality traits, self-efficacy, aging perceptions, and depressive symptoms were assessed. Mediation analyses tested the hypothesis that self-efficacy and aging perceptions would mediate the relationship between personality traits and depressive symptoms. RESULTS: All five personality traits were significant predictors of depressive symptoms. Neuroticism was positively associated with depressive symptoms and had the greatest effect compared with the other personality traits. There was a significant indirect effect of neuroticism, extraversion, and conscientiousness on depressive symptoms (including both mediators). The mediating effect of aging perceptions on the relationship between neuroticism and depressive symptoms was the strongest compared with self-efficacy, accounting for approximately 80% of the total indirect effect. CONCLUSION: Our results provide support for interventions aimed at improving self-perceptions related to efficacy and aging in order to reduce depressive symptoms in older adults. Copyright © 2016 John Wiley & Sons, Ltd.

Dimensions of depressive symptoms and cingulate volumes in older adults.

Clinical depression and subthreshold depressive symptoms in older adults have been linked to structural changes in the cingulate gyrus. The cingulate comprises functionally distinct subregions that may have distinct associations with different types, or symptom dimensions, of depression. This study examined the relationship between symptom dimensions of depression and gray matter volumes in the anterior cingulate, posterior cingulate and isthmus of the cingulate in a nonclinical sample. The study included 41 community-dwelling older adults between the ages of 55 and 81. Participants received a structural magnetic resonance imaging scan and completed the Center for Epidemiologic Studies Depression Scale. Subscale scores for depressed mood, somatic symptoms and lack of positive affect were calculated, and Freesurfer was used to extract cingulate gray matter volumes. Regression analyses were conducted to examine the relationship between depressive symptoms and volumes of cingulate subregions while controlling for sex, age and estimated total intracranial volume. Higher scores on the depressed mood subscale were associated with larger volumes in the left posterior cingulate and smaller volumes in the isthmus cingulate. Higher scores on the somatic symptoms subscale were significantly related to smaller volumes in the posterior cingulate. A trend was observed for a positive relationship between higher scores on the lack of positive affect subscale and larger volumes in the anterior cingulate cortex. These results are consistent with previous findings of altered cingulate volumes with increased depressive symptomatology and suggest specific symptom dimensions of depression may differ in their relationship with subregions of the cingulate.

Genetic Moderators of the Impact of Physical Activity on Depressive Symptoms.

BACKGROUND: Converging evidence suggests that physical activity is an effective intervention for both clinical depression and sub-threshold depressive symptoms; however, findings are not always consistent. These mixed results might reflect heterogeneity in response to physical activity, with some subgroups of individuals responding positively, but not others. OBJECTIVES: 1) To examine the impact of genetic variation and sex on changes in depressive symptoms in older adults after a physical activity (PA) intervention, and 2) to determine if PA differentially improves particular symptom dimensions of depression. DESIGN: Randomized controlled trial. SETTING: Four field centers (Cooper Institute, Stanford University, University of Pittsburgh, and Wake Forest University). PARTICIPANTS: 396 community-dwelling adults aged 70-89 years who participated in the Lifestyle Interventions and Independence for Elders Pilot Study (LIFE-P). INTERVENTION: 12-month PA intervention compared to an education control. MEASUREMENTS: Polymorphisms in the serotonin transporter (5-HTT), brain-derived neurotrophic factor (BDNF), and apolipoprotein E (APOE) genes; 12-month change in the Center for Epidemiologic Studies Depression Scale total score, as well as scores on the depressed affect, somatic symptoms, and lack of positive affect subscales. RESULTS: Men randomized to the PA arm showed the greatest decreases in somatic symptoms, with a preferential benefit in male carriers of the BDNF Met allele. Symptoms of lack of positive affect decreased more in men compared to women, particularly in those possessing the 5-HTT L allele, but the effect did not differ by intervention arm. APOE status did not affect change in depressive symptoms. CONCLUSIONS: Results of this study suggest that the impact of PA on depressive symptoms varies by genotype and sex, and that PA may mitigate somatic symptoms of depression more than other symptoms. The results suggest that a targeted approach to recommending PA therapy for treatment of depression is viable.