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The fact that tyrosine increases dopamine availability that, in turn, may enhance cognitive performance has led to numerous studies on healthy young participants taking tyrosine as a food supplement. As a result of this dietary intervention, participants show performance increases in working memory and executive functions. However, the potential association between habitual dietary tyrosine intake and cognitive performance has not been investigated to date. The present study aims at clarifying the association of episodic memory (EM), working memory (WM) and fluid intelligence (Gf), and tyrosine intake in younger and older adults. To this end, we acquired habitual tyrosine intake (food frequency questionnaire) from 1724 participants of the Berlin Aging Study II (1383 older adults, 341 younger adults) and modelled its relations to cognitive performance assessed in a broad battery of cognitive tasks using structural equation modeling. We observed a significant association between tyrosine intake and the latent factor capturing WM, Gf, and EM in the younger and the older sample. Due to partial strong factorial invariance between age groups for a confirmatory factor analysis on cognitive performance, we were able to compare the relationship between tyrosine and cognition between age groups and found no difference. Above and beyond previous studies on tyrosine food supplementation the present result extend this to a cross-sectional association between habitual tyrosine intake levels in daily nutrition and cognitive performance (WM, Gf, and EM). This corroborates nutritional recommendations that are thus far derived from single-dose administration studies.

Islamist radicalization is a global phenomenon and is currently a major subject of concern. Our objective is to systematically review the literature for evidence exploring risk and protective factors for and against Islamist radicalization. The following databases PsycINFO, Web of Science, Embase, PubMed and Google Scholar (complementary research) were systematically searched for English and WISO for German papers. The results of the review lend support to the notion that accumulated risk factors in the absence of protective factors may accelerate the process of Islamist radicalization. Consensus is increasing in respect to the empirical evidence that there is neither a typical set of characteristics nor a specific personality profile those individuals who come to islamistically radicalize share. Despite this heterogeneity, the current review captures eight domains of risk and protective factors for Islamist radicalization. [ABSTRACT FROM AUTHOR]

Introduction: There is a significant demand for interventions that reduce distress related to auditory verbal hallucinations (AVHs). AVH distress is associated with the way voice hearers relate with AVHs. We aimed to establish the feasibility of a randomized controlled trial to demonstrate that adding "Relating Therapy" (RT) to treatment as usual (TAU) is superior to TAU in reducing AVH distress. Methods: We conducted a multicenter, parallel, single-blind, randomized controlled feasibility trial in five mental health centers in Germany. Participants were ≥19 years of age, had persistent and distressing AVHs, and had a diagnosis of a schizophrenia-spectrum disorder. RT was delivered over a maximum of 16 sessions within 5 months. Blind assessments were conducted at baseline and at 5 and 9 months. Feasibility outcomes were the number of patients recruited and retained, and safety and therapist adherence. The primary endpoint was the distress factor score of the AVH subscale of the Psychotic Symptoms Rating Scales at 9 months. Results: Eighty-five of 177 enrolled participants were randomized into RT + TAU (n = 43) or TAU (n = 42). Feasibility was excellent with 87% retention at 9 months, 86% reaching treatment uptake criteria, 98% therapist adherence, and no unexpected serious adverse reactions. Compared to TAU, RT + TAU showed nonsignificant trends toward less AVH distress (b = −2.40, SE = 1.52, p = 0.121, 90% CI (−4.94 to 0.15) and stronger improvement on all but one of the secondary outcomes. Conclusion: A randomized controlled trial of RT is feasible, safe, and well accepted. Our results provide an encouraging basis to further test the efficacy of RT in a definitive multicenter trial. [ABSTRACT FROM AUTHOR]

Background Diagnostic criteria for mental disorders are subject to change. This is particularly true for schizophrenia, whose diagnostic criteria in the current DSM-5 bear little resemblance to what Kraepelin once named "dementia praecox" and Bleuler termed "the schizophrenias." The present study reports results from a survey of experts on two core topics of schizophrenia: (a) whether subsequent editions of the DSM should once again give the Schneiderian first-rank symptoms (FRS; eg, thought broadcasting) the prominent role they had in the DSM-IV and (b) whether the currently quite narrow definition of hallucinations in the DSM-5 requiring them to be vivid and clear and have the full force and impact of normal perceptions should be broadened to incorporate perceptual-like phenomena that the individual can differentiate from proper perceptions but still perceives as real and externally generated. Hypothesis The aim of the survey was to learn about experts' opinions with no clear hypotheses. Study Design International experts on schizophrenia were recruited via various sources and invited to participate in a short online survey. The final sample comprised 136 experts with a subgroup of 53 experts with verified identity and at least 6 years of clinical and/or research experience. Study Results Slightly more experts voted in favor (49.3%) of returning FRS to the prominent role they had in earlier versions of the DSM than against (34.6%). Approximately four out of five experts agreed that the definition of hallucinations in the DSM should be expanded. According to the results, alongside internal symptoms that are phenomenologically indistinguishable from true perceptions, sensory intrusions that the holder is convinced were inserted from another source (ie, not self-generated) should be included in the definition. Conclusions While a large majority of experts recommend a change in the definition of hallucinations, the experts' opinions on FRS are more mixed. We hope that this article will stimulate future studies targeting the diagnostic relevance of these symptoms and encourage discussion about the definition of core psychotic symptoms and the diagnostic criteria for the upcoming edition of the DSM. [ABSTRACT FROM AUTHOR]

The two hemispheres of the human brain differ functionally and structurally. Despite over a century of research, the extent to which brain asymmetry is influenced by sex, handedness, age, and genetic factors is still controversial. Here we present the largest ever analysis of subcortical brain asymmetries, in a harmonized multi-site study using meta-analysis methods. Volumetric asymmetry of seven subcortical structures was assessed in 15,847 MRI scans from 52 datasets worldwide. There were sex differences in the asymmetry of the globus pallidus and putamen. Heritability estimates, derived from 1170 subjects belonging to 71 extended pedigrees, revealed that additive genetic factors influenced the asymmetry of these two structures and that of the hippocampus and thalamus. Handedness had no detectable effect on subcortical asymmetries, even in this unprecedented sample size, but the asymmetry of the putamen varied with age. Genetic drivers of asymmetry in the hippocampus, thalamus and basal ganglia may affect variability in human cognition, including susceptibility to psychiatric disorders.

Background: The association of impaired dopaminergic neurotransmission with the development and maintenance of alcohol use disorder is well known. More specifically, reduced dopamine D2/3 receptors in the striatum of subjects with alcohol dependence (AD) compared to healthy controls have been found in previous studies. Furthermore, alterations of gamma‐aminobutyric acid (GABA) and glutamate (Glu) levels in the anterior cingulate cortex (ACC) of AD subjects have been documented in several studies. However, the interaction between cortical Glu levels and striatal dopamine D2/3 receptors has not been investigated in AD thus far. Methods: This study investigated dopamine D2/3 receptor availability via 18F‐fallypride positron emission tomography (PET) and GABA as well as Glu levels via magnetic resonance spectroscopy (MRS) in 19 detoxified AD subjects, 18 healthy controls (low risk, LR) controls and 19 individuals at high risk (HR) for developing AD, carefully matched for sex, age and smoking status. Results: We found a significant negative correlation between GABA levels in the ACC and dopamine D2/3 receptor availability in the associative striatum of LR but not in AD or HR individuals. Contrary to our expectations, we did not observe a correlation between Glu concentrations in the ACC and striatal D2/3 receptor availability. Conclusions: The results may reflect potential regulatory cortical mechanisms on mesolimbic dopamine receptors and their disruption in AD and individuals at high risk, mirroring complex neurotransmitter interactions associated with the pathogenesis of addiction. This is the first study combining 18F‐fallypride PET and MRS in AD subjects and individuals at high risk. [ABSTRACT FROM AUTHOR]

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Objectives: The immediate living environment might, like other lifestyle factors, be significantly related to mental well‐being. The current study addresses the question whether five relevant subjective home environment variables (i.e., protection from disturbing nightlight, daylight entering the home, safety at home, quality of window views, and noise disturbance) are associated with levels of self‐reported depression over and above well‐known sociodemographic and common lifestyle variables. Methods: Data from the Hamburg City Health Study (HCHS) were analyzed. In N = 8757 with available PHQ‐9 depression data, multiple linear regression models were computed, with demographic data, lifestyle variables, and variables describing the subjective evaluation of the home environment. Results: The model explained 15% of variance in depression levels, with ratings for the subjective evaluation of home environment accounting for 6%. Better protection from disturbing light at night, more daylight entering the home, feeling safer, and perceived quality of the window views, were all significantly associated with lower, while more annoyance by noise was associated with higher levels of self‐reported depression. Results did not differ if examining a sample of the youngest (middle‐aged participants: 46−50 years) versus oldest (70−78 years) participants within HCHS. Conclusion: Beyond studying the role of lifestyle factors related to self‐reported depression, people's homes may be important for subclinical levels of depression in middle and older age, albeit the direction of effects or causality cannot be inferred from the present study. The development of a consensus and tools for a standardized home environment assessment is needed. [ABSTRACT FROM AUTHOR]