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Substance-dependent individuals often lack the ability to adjust decisions flexibly in response to the changes in reward contingencies. Prediction errors (PEs) are thought to mediate flexible decision-making by updating the reward values associated with available actions. In this study, we explored whether the neurobiological correlates of PEs are altered in alcohol dependence. Behavioral, and functional magnetic resonance imaging (fMRI) data were simultaneously acquired from 34 abstinent alcohol-dependent patients (ADP) and 26 healthy controls (HC) during a probabilistic reward-guided decision-making task with dynamically changing reinforcement contingencies. A hierarchical Bayesian inference method was used to fit and compare learning models with different assumptions about the amount of task-related information subjects may have inferred during the experiment. Here, we observed that the best-fitting model was a modified Rescorla-Wagner type model, the “double-update” model, which assumes that subjects infer the knowledge that reward contingencies are anti-correlated, and integrate both actual and hypothetical outcomes into their decisions. Moreover, comparison of the best-fitting model's parameters showed that ADP were less sensitive to punishments compared to HC. Hence, decisions of ADP after punishments were loosely coupled with the expected reward values assigned to them. A correlation analysis between the model-generated PEs and the fMRI data revealed a reduced association between these PEs and the BOLD activity in the dorsolateral prefrontal cortex (DLPFC) of ADP. A hemispheric asymmetry was observed in the DLPFC when positive and negative PE signals were analyzed separately. The right DLPFC activity in ADP showed a reduced correlation with positive PEs. On the other hand, ADP, particularly the patients with high dependence severity, recruited the left DLPFC to a lesser extent than HC for processing negative PE signals. These results suggest that the DLPFC, which has been linked to adaptive control of action selection, may play an important role in cognitive inflexibility observed in alcohol dependence when reinforcement contingencies change. Particularly, the left DLPFC may contribute to this impaired behavioral adaptation, possibly by impeding the extinction of the actions that no longer lead to a reward.
The aim was to analyze the risk of hip fracture in German primary care patients with dementia. This study included patients aged 65-90 from 1072 primary care practices who were first diagnosed with dementia between 2010 and 2013. Controls were matched (1:1) to cases for age, sex, and type of health insurance. The primary outcome was the diagnosis of hip fracture during the three-year follow-up period. A total of 53,156 dementia patients and 53,156 controls were included. A total of 5.3% of patients and 0.7% of controls displayed hip fracture after three years. Hip fracture occurred more frequently in dementia subjects living in nursing homes than in those living at home (9.2% versus 4.3%). Dementia, residence in nursing homes, and osteoporosis were risk factors for fracture development. Antidementia, antipsychotic, and antidepressant drugs generally had no significant impact on hip fracture risk when prescribed for less than six months. Dementia increased hip fracture risk in German primary care practices.
The aim was to analyze the risk of hip fracture in German primary care patients with dementia. This study included patients aged 65-90 from 1072 primary care practices who were first diagnosed with dementia between 2010 and 2013. Controls were matched (1:1) to cases for age, sex, and type of health insurance. The primary outcome was the diagnosis of hip fracture during the three-year follow-up period. A total of 53,156 dementia patients and 53,156 controls were included. A total of 5.3% of patients and 0.7% of controls displayed hip fracture after three years. Hip fracture occurred more frequently in dementia subjects living in nursing homes than in those living at home (9.2% versus 4.3%). Dementia, residence in nursing homes, and osteoporosis were risk factors for fracture development. Antidementia, antipsychotic, and antidepressant drugs generally had no significant impact on hip fracture risk when prescribed for less than six months. Dementia increased hip fracture risk in German primary care practices.
We investigated the efficacy of reminiscence therapy (RT) on symptoms of depression in patients with mild to moderate dementia. Out of 227 patients with mild to moderate dementia from a specialized physician’s office, 27 pairs (N = 54; mean age 79.04 ± 6.16 years) who had either received treatment as usual (TAU) or TAU combined with RT, were matched retrospectively according to age as well as cognitive and depressive symptom scores. After controlling for age and sex, symptoms of depression significantly decreased over time in the RT group compared to TAU (F1,52 = 4.36; p < .05). RT is a promising option for the treatment of depression in mild to moderate dementia. Larger randomized-controlled trials are needed.
Background: The aim of the present study was to investigate the psychometric characteristics of the Perceived Stress Scale (PSS) in a sample of dementia patients and their spousal caregivers. Methods: We investigated the reliability and validity of the 14-item PSS in a sample of 80 couples, each including one spouse who had been diagnosed with mild to moderate dementia (mean age 75.55, SD = 5.85, 38.7% female) and one spousal caregiver (mean age 73.06, SD = 6.75, 61.3% female). We also examined the factor structure and sensitivity of the scale with regard to gender differences. Results: Exploratory factor analysis of the PSS revealed a two-factor solution for the scale; the first factor reflected general stress while the second factor consisted of items reflecting the perceived ability to cope with stressors. A confirmatory factor analysis verified that the data were a better fit for the two-factor model than a one-factor model. The two factors of the PSS showed good reliability for patients as well as for caregivers ranging between alpha = 0.73 and alpha = 0.82. Perceived stress was significantly positively correlated with depressive symptomatology in both caregivers and patients. Mean PSS scores did not significantly differ between male and female patients nor did they differ between male and female caregivers. Conclusion: The present data indicate that the PSS provides a reliable and valid measure of perceived stress in dementia patients and their caregivers.
The goal of this study was to determine the prevalence of depression and its risk factors in patients with late-onset rheumatoid arthritis (RA) treated in German primary care practices. Longitudinal data from general practices (n=1072) throughout Germany were analyzed. Individuals initially diagnosed with RA (2009-2013) were identified, and 7301 patients were included and matched (1:1) to 7301 controls. The primary outcome measure was the initial diagnosis of depression within 5 years after the index date in patients with and without RA. Cox proportional hazards models were used to adjust for confounders. The mean age was 72.2 years (SD: 7.6 years). A total of 34.9 % of patients were men. Depression diagnoses were present in 22.0 % of the RA group and 14.3 % of the control group after a 5-year follow-up period (p < 0.001). In the multivariate regression model, RA was a strong risk factor for the development of depression (HR: 1.55, p < 0.001). There was significant interaction of RA and diagnosed inflammatory polyarthropathies (IP) (RA*IP interaction: p < 0.001). Furthermore, dementia, cancer, osteoporosis, hypertension, and diabetes were associated with a higher risk of developing depression (p values < 0.001). The risk of depression is significantly higher in patients with late-onset RA than in patients without RA for subjects treated in primary care practices in Germany. RA patients should be screened routinely for depression in order to ensure improved treatment and management.
Rationale: Advances in neurocomputational modeling suggest that valuation systems for goal-directed (deliberative) on one side, and habitual (automatic) decision-making on the other side may rely on distinct computational strategies for reinforcement learning, namely model-free vs. model-based learning. As a key theoretical difference, the model-based system strongly demands cognitive functions to plan actions prospectively based on an internal cognitive model of the environment, whereas valuation in the model-free system relies on rather simple learning rules from operant conditioning to retrospectively associate actions with their outcomes and is thus cognitively less demanding. Acute stress reactivity is known to impair model-based but not model-free choice behavior, with higher working memory capacity protecting the model-based system from acute stress. However, it is not clear which impact accumulated real life stress has on model-free and model-based decision systems and how this influence interacts with cognitive abilities. Methods: We used a sequential decision-making task distinguishing relative contributions of both learning strategies to choice behavior, the Social Readjustment Rating Scale questionnaire to assess accumulated real life stress, and the Digit Symbol Substitution Test to test cognitive speed in 95 healthy subjects. Results: Individuals reporting high stress exposure who had low cognitive speed showed reduced model-based but increased model-free behavioral control. In contrast, subjects exposed to accumulated real life stress with high cognitive speed displayed increased model-based performance but reduced model-free control. Conclusion: These findings suggest that accumulated real life stress exposure can enhance reliance on cognitive speed for model-based computations, which may ultimately protect the model-based system from the detrimental influences of accumulated real life stress. The combination of accumulated real life stress exposure and slower information processing capacities, however, might favor model-free strategies. Thus, the valence and preference of either system strongly depends on stressful experiences and individual cognitive capacities.
Objectives: In patients with early-stage dementia and their caregiving partners, reciprocal dyadic coping (DC) is crucial for preventing or reducing depressive symptoms in both partners. This study examines the relationships between ‘own DC’ and ‘perceived partner DC’ with depressive symptoms in couples coping with dementia on individual (actor effects) and cross-person (partner effects) levels.
Method: 164 individuals (82 patients with early-stage dementia and their 82 caregiving partners; ND = 82 dyads) participated in this prospective study with measures (DC, depressive symptoms, and dementia severity) taken at baseline and at six months. Each partner evaluated their own and the perceived partner DC. Actor–partner interdependence models were applied to the resulting four independent evaluations.
Results: Results differed substantially between patients and caregivers. DC was significantly related to patients’ but not to caregivers’ depressive symptoms, when adjustments were made for individual coping. Perceived partner DC showed a negative association with depressive symptoms in patients, whereas own DC was adversely related for actor as well as for partner effects across individuals.
Conclusion: The adverse association between the own DC of the caregiver and the patient on depressive symptoms of the patient might be due to inappropriate efforts or to the loss of autonomy as a care-receiver. DC is important in both patients and caregivers, as shown by the negative association between perceived partner DC and depressive symptoms in the patients, which might inform interventions that target the couple as a whole.
Cities and Mental Health
(2017)
Background: More than half of the global population currently lives in cities, with an increasing trend for further urbanization. Living in cities is associated with increased population density, traffic noise and pollution, but also with better access to health care and other commodities. Methods: This review is based on a selective literature search, providing an overview of the risk factors for mental illness in urban centers. Results: Studies have shown that the risk for serious mental illness is generally higher in cities compared to rural areas. Epidemiological studies have associated growing up and living in cities with a considerably higher risk for schizophrenia. However, correlation is not causation and living in poverty can both contribute to and result from impairments associated with poor mental health. Social isolation and discrimination as well as poverty in the neighborhood contribute to the mental health burden while little is known about specific inter actions between such factors and the built environment. Conclusion: Further insights on the interaction between spatial heterogeneity of neighborhood resources and socio-ecological factors is warranted and requires interdisciplinary research.