How Loneliness Gets Under the Skin: Inflammation Mediates the Relationship Between Loneliness and Gait Speed.

OBJECTIVE: Loneliness is linked to interleukin 6 (IL-6), a marker of systemic inflammation, which chronically has deleterious effects on physical and mental health across the adult life span. This study investigated cross-sectional relationships among loneliness, IL-6, demographics, multimorbidity, depression, obesity, friendship quantity, and slowed gait. METHODS: Data from the Midlife Development in the United States Biomarker Project, a national adult sample ( N = 822; age range, 26-78 years) was used for this study. The PROCESS macro tested the hypothesis that IL-6 would mediate the relationship between loneliness and gait, after adjusting for demographic and health risk factors. RESULTS: Age ( ß = 0.292, p < .001), sex ( ß = 0.197, p < .001), body mass index (BMI, ß = 0.374, p < .001), waist-hip ratio ( ß = 0.242, p < .001), and loneliness ( ß = 0.089, p = .025) but not multimorbidity ( ß = 0.043, p = .20), depression history ( ß = 0.022, p = .47), depression symptoms ( ß = 0.036, p = .28), and number of friends ( ß = 0.022, p = .46) contributed to the variance in IL-6. Serial mediation analyses supported the chained effect of loneliness on walking time through BMI and IL-6. Results also showed specific indirect effects of BMI and IL-6 on walking time, suggesting more than one pathway by which loneliness influences health. CONCLUSIONS: These results suggest that loneliness may increase the risk of systemic inflammation, leading to slowed gait and adverse health outcomes. Psychosocial interventions that address loneliness may provide an optimal treatment target for reducing inflammation and preventing declines in health.

How Will I Be Perceived: The Role of Trauma-Related Shame in the Relationship Between Psychological Distress and Expectations of Disclosure Among Survivors of Sexual Victimization.

Sexual assault is a serious physical and psychological concern worldwide. Various negative psychological outcomes are associated with survivor well-being, including depression, posttraumatic stress disorder (PTSD), depressive symptoms, and trauma-related shame. Opportunities for emotional expression and processing have been shown to be beneficial among survivors of trauma; however, survivors of sexual victimization may be reticent to disclose details of their traumatic experience, particularly to formal sources of support. Trauma-related shame (e.g., negative evaluations of self, feelings of worthlessness, and powerlessness) has been shown to negatively impact expectations of disclosure, as some survivors may fear being blamed or judged. Limited research exists on the impact of psychological distress on survivors' expectations of disclosure. The current study investigated whether psychological distress (i.e., depressive and PTSD symptoms) is associated with expectations of disclosure (positive vs. negative) through trauma-related shame among survivors of sexual victimization. Participants, recruited from a primarily Hispanic-serving institution, participated in the present study. Participants (N = 86) completed measures of PTSD and depression symptom severity, trauma-related shame, and expectations of disclosure. Results revealed that psychological distress severity was associated with negative expectations of disclosure through trauma-related shame (b = 0.682, p < .05, 95% confidence interval [CI] [0.197, 1.367]), but not positive expectation (b = -0.068, p = .417, 95% CI [-0.523, 0.155]). Our findings have implications for prognosis and treatment for survivors of sexual victimization, particularly among LatinX populations.

Cumulative Effect of Head Injuries on Nonmotor Outcomes in Parkinson's Disease.

OBJECTIVE: Parkinson's disease (PD) is a neurodegenerative movement disorder that is a result of dopamine depletion in the basal ganglia. Individuals with a PD diagnosis experience motor symptoms (e.g., tremors) and nonmotor symptoms (e.g., cognitive decline). Previous studies suggest that progression of cognitive dysfunction in other neurologic populations can be predicted by cumulative head injuries. The study examined the association between lifelong number of head injuries and nonmotor outcomes (cognitive complaints, depression, and quality of life). METHODS: Participants consisted of 3,483 individuals with PD diagnoses who were enrolled in the Fox Insight study. Participants completed a self-report questionnaire to quantify the number of head injuries experienced throughout life. Participants also completed measures of nonmotor outcomes (cognitive complaints, depression, and quality of life) every 6 months over a 3-year period. RESULTS: Cognitive complaints were more common among those experiencing more head injuries. Further, more severe depression and greater difficulties in quality of life were reported among individuals experiencing a greater number of head injuries. Additional analyses revealed the effect between cognitive complaints and number of head injuries was driven by individuals who experienced five or more head injuries in their lifetime. CONCLUSIONS: Among individuals with PD, a patient report of past head injuries may have prognostic implications for important nonmotor outcomes. Report of multiple head injuries may be particularly concerning.

Physical inactivity links depressive symptoms and cognitive functioning among individuals with Parkinson's disease.

OBJECTIVE: Parkinson's disease (PD) is a neurodegenerative disorder caused by disruption of dopamine-producing cells. PD is associated with motor symptoms and nonmotor symptoms including depression and cognitive impairment. Past research suggests an association between depression and cognitive impairment in PD. Physical activity may have a therapeutic effect on both depression and cognitive impairment. The present study investigates if physical activity mediates the association between depressive symptoms and cognition in a longitudinal sample of individuals with PD. METHOD: Participants include individuals newly diagnosed with PD (N = 487) enrolled in the Parkinson's Progression Marker Initiative (PPMI). Participants completed an array of neuropsychological tests over the course of 5 years, as well as questionnaires of depression and physical activity. Between-person and within-person effects of depression and cognition mediated through physical activity were analyzed using structural equation modeling. RESULTS: A significant direct effect demonstrated depression was associated with worse global cognitive functioning. Furthermore, there was a significant indirect within-person effect, indicating that physical activity fully mediated the association between depression and cognition. Individuals who became more depressed over time became less physically active and subsequently experienced cognitive decline over the 5-year period. CONCLUSIONS: Findings have implications for prognostic detection and/or the role of physical activity interventions to buffer effects of depression on cognitive impairment among individuals diagnosed with PD. Physical interventions may potentially be implemented among depressed persons to preserve cognitive functioning. Worsened depression early during PD may be a risk factor for inactivity and cognitive diminishment. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Apathy as a Within-Person Mediator of Depressive Symptoms and Cognition in Parkinson's Disease: Longitudinal Mediation Analyses.

OBJECTIVE: Greater depressive symptoms are associated with worse cognitive functions in Parkinson's disease (PD); however, it is unclear what underlying factors drive this association. Apathy commonly develops in PD and may be a pathway through which depressive symptoms negatively influence cognition. Prior research examining depressive symptoms, apathy, and cognition in PD is limited by being predominantly cross-sectional. This study examined the role of apathy as a within- and between-person mediator for the longitudinal relationships between depression severity and cognitive functioning in patients with early PD. METHODS: Participants included 487 individuals newly diagnosed with PD followed annually for up to 5 years by the Parkinson's Progression Marker Initiative. At each visit, participants completed depressive symptom measures, apathy ratings, and cognitive tests. Multi-level structural equation models examined both the within- and between-person effects of depressive symptoms on cognition through apathy, controlling for demographics and motor severity. RESULTS: At the within-person level, apathy mediated the association between depressive symptoms and select cognitive functions (global cognition, attention/working memory, visuospatial functions, and immediate verbal memory; indirect effects, bootstrap p's <0.05). Significant between-person direct effects were found for depressive symptoms predicting apathy (boostrap p <0.001) and lower scores on most cognitive tests (bootstrap p's <0.05). However, the indirect effects did not reach significance, suggesting between-person mediation did not occur. CONCLUSION: Findings suggest worsening of depressive symptoms over time in patients with PD may be a risk factor for increased apathy and subsequent decline in specific cognitive functions.