Dementia Caregiver Burden: A Research Update and Critical Analysis

Purpose of Review: This article provides an updated review of the determinants of caregiver burden and depression, with a focus on care demands and especially the differential effects of various neuropsychiatric symptoms or symptom clusters. Moreover, studies on caregivers for frontotemporal and Lewy body dementias were referred to in order to identify differences and similarities with the mainstream literature based largely on Alzheimer caregivers. Recent Findings: As a group, neuropsychiatric symptoms are most predictive of caregiver burden and depression regardless of dementia diagnosis, but the effects appear to be driven primarily by disruptive behaviors (e.g., agitation, aggression, disinhibition), followed by delusions and mood disturbance. Disruptive behaviors are more disturbing partly because of the adverse impact on the emotional connection between the caregiver and the care-recipient and partly because they exacerbate difficulties in other domains (e.g., caring for activities of daily living). In behavioral variant frontotemporal dementia, not only are these disruptive behaviors more prominent but they are also more disturbing due to the care-recipient’s insensitivity to others’ feelings. In Lewy body dementia, visual hallucinations also appear to be distressing. Summary: The disturbing nature of disruptive behaviors cuts across dementia conditions, but the roles played by symptoms that are unique or particularly serious in a certain condition need to be explored further

Cross‐cultural comparison of symptom networks in late‐life major depressive disorder: Yoruba Africans and the Spanish Population

Background: The concept of European psychologisation of depression versus somatisation in non-European populations has been the basis of several studies of cultural psychopathology in the general population. Little is currently known about cross-cultural differences and similarities in late-life depression symptom reporting. We cross-culturally compared symptom reporting in the context of Major Depressive Disorder (MDD) among community-dwelling older adults from Spain and Nigeria. Methods: We relied on data from two household multistage probability samples comprising 3,715 persons aged 65 years or older in the Spanish and Nigerian populations. All participants underwent assessments for MDD using the World Mental Health Survey version of the Composite International Diagnostic Interview. Cross-cultural comparison of broad somatic and psychological categories as well as relationship and influence of individual symptoms were analysed using the Symptom Network Analysis approach. Results: Current MDD was diagnosed in 232 and 195 older persons from Spain and Nigeria, respectively. The symptom network of the two samples were invariant in terms of global strength, S(GSPAIN , GNIGERIA ) = 7.56, P = .06, with psychological and somatic symptoms demonstrating centrality in both countries. However, country-specific relationships and influence of individual symptoms were found in the network structure of both samples, M(GSPAIN , GNIGERIA ) = 2.95, P < .01. Conclusion: Broad somatic and psychological symptoms categories contributed to the structural network of older Africans and their peers from the Spanish population. Variations in the relationship and influence of individual symptoms suggests that the functional and "communicative" role of individual symptoms may be differentiated by context specific imperatives. J Am Geriatr Soc 68:-, 2020.Wellcome TrustUnión EuropeaMinisterio de Economía y CompetitividadInstituto de Salud Carlos IIIDepto. de Medicina Legal, Psiquiatría y PatologíaFac. de MedicinaTRUEpu

The IMAGEN study: a decade of imaging genetics in adolescents

Imaging genetics offers the possibility of detecting associations between genotype and brain structure as well as function, with effect sizes potentially exceeding correlations between genotype and behavior. However, study results are often limited due to small sample sizes and methodological differences, thus reducing the reliability of findings. The IMAGEN cohort with 2000 young adolescents assessed from the age of 14 onwards tries to eliminate some of these limitations by offering a longitudinal approach and sufficient sample size for analyzing gene-environment interactions on brain structure and function. Here, we give a systematic review of IMAGEN publications since the start of the consortium. We then focus on the specific phenotype 'drug use' to illustrate the potential of the IMAGEN approach. We describe findings with respect to frontocortical, limbic and striatal brain volume, functional activation elicited by reward anticipation, behavioral inhibition, and affective faces, and their respective associations with drug intake. In addition to describing its strengths, we also discuss limitations of the IMAGEN study. Because of the longitudinal design and related attrition, analyses are underpowered for (epi-) genome-wide approaches due to the limited sample size. Estimating the generalizability of results requires replications in independent samples. However, such densely phenotyped longitudinal studies are still rare and alternative internal cross-validation methods (e.g., leave-one out, split-half) are also warranted. In conclusion, the IMAGEN cohort is a unique, very well characterized longitudinal sample, which helped to elucidate neurobiological mechanisms involved in complex behavior and offers the possibility to further disentangle genotype × phenotype interactions

Induction and Consolidation of Calcium-Based Homo- and Heterosynaptic Potentiation and Depression.

The adaptive mechanisms of homo- and heterosynaptic plasticity play an important role in learning and memory. In order to maintain plasticity-induced changes for longer time scales (up to several days), they have to be consolidated by transferring them from a short-lasting early-phase to a long-lasting late-phase state. The underlying processes of this synaptic consolidation are already well-known for homosynaptic plasticity, however, it is not clear whether the same processes also enable the induction and consolidation of heterosynaptic plasticity. In this study, by extending a generic calcium-based plasticity model with the processes of synaptic consolidation, we show in simulations that indeed heterosynaptic plasticity can be induced and, furthermore, consolidated by the same underlying processes as for homosynaptic plasticity. Furthermore, we show that by local diffusion processes the heterosynaptic effect can be restricted to a few synapses neighboring the homosynaptically changed ones. Taken together, this generic model reproduces many experimental results of synaptic tagging and consolidation, provides several predictions for heterosynaptic induction and consolidation, and yields insights into the complex interactions between homo- and heterosynaptic plasticity over a broad variety of time (minutes to days) and spatial scales (several micrometers).Open-Access-Publikationsfonds 2016peerReviewe