Dynamic body weight and body composition changes in response to subordination stress

Social stress is prevalent in many facets of modern society. Epidemiological data suggest that stress is linked to the development of overweight, obesity and metabolic disease. Although there are strong associations between the incidence of obesity with stress and elevated levels of hormones such as cortisol, there are limited animal models to allow investigation of the etiology of increased adiposity resulting from exposure to stress. Perhaps more importantly, an animal model that mirrors the consequences of stress in humans will provide a vehicle to develop rational clinical therapy to treat or prevent adverse outcomes from exposure to chronic social stress. In the visible burrow system (VBS) model of chronic social stress mixed gender colonies are housed for 2 week periods during which male rats of the colony quickly develop a dominance hierarchy. We found that social stress has significant effects on body weight and body composition such that subordinate rats progressively develop characteristics of obesity that occurs, in part, through neuroendocrine alterations and changes in food intake amount. Although subordinate rats are hyperphagic following social stress they do not increase their intake of sucrose solution as control and dominants do suggesting that they are anhedonic. Consumption of a high fat diet does not appear to affect development of a social hierarchy and appears to enhance the effect that chronic stress has on body composition. The visible burrow system (VBS) model of social stress may be a potential laboratory model for studying stress-associated metabolic disease, including the metabolic syndrome.     

Attentional modulation by reward and punishment cues in relation to depressive symptoms

Background and objectives

Research indicates that individuals at-risk for depression are characterized by high sensitivity to loss and reduced sensitivity to reward. Moreover, it has been shown that attentional bias plays an important role in depression vulnerability. The current study aimed to examine the interplay between these risk factors for depression by examining the development of attentional bias toward reward and loss signals in dysphoric participants (individuals with elevated levels of depressive symptoms).

Methods

Shapes were conditioned to reward and loss and subsequently presented in a dot probe task in a sample of dysphoric and nondysphoric participants.

Results

Nondysphoric individuals oriented towards reward-related signals whereas dysphoric individuals failed to develop a reward-related attentional bias. This attentional effect was observed in the absence of group differences in motivational factors. No group differences were found for attentional bias for loss-related signals, despite the fact that dysphoric individuals performed worse in response to losing.

Limitations

The current sample is not clinical thus generalization to clinical depression is not warranted.

Conclusions

We argue that impaired early attentional processing of rewards are an important cognitive risk factor for anhedonic symptoms in persons with dysphoria.     

Anhedonia in Japanese patients with Parkinson's disease: analysis using the Snaith-Hamilton Pleasure Scale

Background

Anhedonia, a lowered ability to experience physical or social pleasure, has recently been recognized as a non-motor symptom of Parkinson's disease.

Objective

To identify the frequency of anhedonia and the factors influencing hedonic tone in Japanese patients with Parkinson's disease.

Patients and methods

We recruited 86 consecutive outpatients with a clinical diagnosis of PD attending two Japanese hospitals (one university hospital and one community hospital) in February 2010. We used the self-rating Snaith–Hamilton Pleasure Scale (SHAPS) translated into Japanese language from the original English version to assess and quantify hedonic tone as a subjectively experienced phenomenon. We studied the association of anhedonia with the variables age, age at onset, gender, disease duration, disease severity and antiparkinsonian drugs.

Results

Thirty-nine patients (45%) were male and 47 (55%) were female. Mean age was 72.01 ± 9.07 (49–89) years, with mean age at onset of 64.93 ± 11.42 (31–88) years. Mean disease duration was 7.20 ± 5.54 (1–23) years. The mean Hoehn and Yahr scale was 2.76 ± 0.78. The mean SHAPS score of the total sample was 1.19 ± 1.86. The SHAPS score of 14 patients (16.3%) was 3 or more, indicating anhedonia. The mean SHAPS score was lower in patients taking pramipexole (0.58 ± 0.97) than in patients not taking pramipexole (1.57 ± 2.16). Multiple linear regression analysis identified pramipexole as a significant negative influencing factor on the SHAPS score, while disease severity and entacapone treatment were identified as positive influencing factors. The age, onset age, gender, disease duration, and use of pergolide, amantadine, zonisamide, selegiline, anticholinergic agents and droxidopa did not significantly affect the SHAPS score.

Conclusion

Anhedonia is not rare non-motor symptom in Japanese patients with Parkinson's disease. This study suggests an anti-anhedonic property of pramipexole.     

Social deprivation stress is a triggering factor for the emergence of anxiety- and depression-like behaviours and leads to reduced brain BDNF levels in C57BL/6J mice

Stress is a main risk factor that can trigger psychiatric disorders, including anxiety and major depression. Neurotrophins, such as Brain-Derived Neurotrophic Factor (BDNF), have been identified as neuroendocrine effectors involved in the response to stress and in the neurobehavioural changes associated with depression. Aim of this paper was to study the relationship between neuroendocrine activation (circulating corticosterone and brain BDNF levels) and a wide array of depression- and anxiety-like behaviours (anhedonia, behavioural despair, generalised and social anxiety) resulting from exposure to chronic stress. To this end, 3-month-old C57BL/6J male mice were exposed to either chronic disruption of the social structure (SS), to a stable social structure (SG) or to social deprivation (SD), a condition lacking social stimuli. Results show that, despite not developing anhedonia (decreased preference for a sucrose solution), SD mice were characterised by increased emotionality and hypothalamic-pituitary-adrenal axis reactivity in addition to reduced BDNF levels. By contrast, SG and SS mice showed increased anhedonia accompanied by no alterations in the behavioural and neuroendocrine profile. The results here reported indicate that mice exposed to different social housing conditions use different behavioural strategies to cope with external challenges. In addition they suggest that social deprivation might represent a stressful condition triggering the emergence of both anxiety- and depression-like behaviours and clearly indicate BDNF as a main neurobiological variable mediating these responses.     

Amitifadine, a triple monoamine uptake inhibitor, reduces binge drinking and negative affect in an animal model of co-occurring alcoholism and depression symptomatology

The co-occurrence of alcoholism and depression is highly prevalent and difficult to treat. In an animal model of binge drinking that exhibits abstinence-induced behaviors reminiscent of negative affective states, the triple monoamine uptake inhibitor, amitifadine, produced a selective, dose dependent attenuation of binge drinking. Amitifadine also reversed abstinence-induced increases in the intracranial self-stimulation threshold, a model of anhedonia, and immobility in the forced swim test, reflecting behavioral despair. In view of the safety profile of amitifadine in humans, including low risk for weight gain, lack of sexual side effects, and low potential for abuse, we hypothesize that amitifadine will be effective in treating co-occurring alcoholism and depression.     

Anhedonia Following Early-Life Adversity Involves Aberrant Interaction of Reward and Anxiety Circuits and Is Reversed by Partial Silencing of Amygdala Corticotropin-Releasing Hormone Gene

Background

Anhedonia, the diminished ability to experience pleasure, is an important dimensional entity linked to depression, schizophrenia, and other emotional disorders, but its origins and mechanisms are poorly understood. We have previously identified anhedonia, manifest as decreased sucrose preference and social play, in adolescent male rats that experienced chronic early-life adversity/stress (CES). Here we probed the molecular, cellular, and circuit processes underlying CES-induced anhedonia and tested them mechanistically.

Neural activity and diurnal variation of cortisol: evidence from brain electrical tomography analysis and relevance to anhedonia

The medial prefrontal cortex (mPFC), hippocampus, and amygdala are implicated in the regulation of affect and physiological processes, including hypothalamic-pituitary-adrenal (HPA) axis function. Anhedonia is likely associated with dysregulation of these processes. Dense-array resting electroencephalographic and cortisol were obtained from healthy and anhedonic groups. Low-resolution electromagnetic tomography was used to compute intracerebral current density. For the control group, voxelwise analyses found a relationship between current density in beta and gamma bands and steeper cortisol slope (indicative of more adaptive HPA axis functioning) in regions of the hippocampus, parahippocampal gyrus, and mPFC. For the anhedonic group, the mPFC finding was absent. Anhedonia may be characterized by disruptions of mPFC-mediated neuroendocrine regulation, which could constitute a vulnerability to the development of stress-related disorders.     

首发精神分裂症患者快感缺乏的成分特征与相关因素

目的探索首发精神分裂症患者快感缺乏的成分特征及其与临床症状、认知功能和社会功能的相关性。方法纳入符合《国际疾病分类(第10版)》(ICD-10)诊断标准的31例首发精神分裂症患者和33例健康对照组。使用愉快情绪体验量表(TEPS)、阳性和阴性症状量表(PANSS)、重复性成套神经心理状态测验(RBANS)以及个人和社会功能量表(PSP)对患者的快感缺乏情况、精神症状、认知功能和社会功能进行评定。采用Pearson相关分析测查快感缺乏与临床症状、认知功能和社会功能的相关性。结果首发精神分裂症患者TEPS消费性快感评分低于健康对照组,差异有统计学意义[(27.71±5.48)分vs.(31.58±5.92)分,t=2.705,P=0.009]。相关分析显示,首发精神分裂症患者消费性快感缺乏与PANSS、RBANS和PSP评分的相关均无统计学意义(P均0.05)。结论首发精神分裂症患者存在消费性快感缺乏,其消费性快感缺乏可能独立于临床症状、认知功能损害和社会功能损害之外。     

首发精神病患者快感缺失水平与认知功能的关系

目的 探讨首发精神病患者快感缺失水平及其与认知功能的关系,分析其认知功能的影响因素.方法 选取2016年12月-2019年3月在广州医科大学附属脑科医院就诊的符合《精神障碍诊断与统计手册(第5版)》(DSM-5)诊断标准的首发精神病患者143例.采用阳性和阴性症状量表(PANSS)评定患者的精神症状,以其中N2情绪退缩...