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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study examined the prevalence and clinical features of ICD-10-defined neurasthenia (NT) in Chinese-Americans and its relations to other psychiatric disorders. In this community epidemiological survey, the enhanced Composite International Diagnostic Interview [CIDI], with a supplemental NT module, was administered to 1,747 Chinese-Americans, selected with a stratified cluster sampling method. The SCL-90-R was also used for measuring psychiatric morbidity and symptoms. Dimensions of social stress and social support were measured by established instruments. A total of 112 ICD-10 NT subjects (6.4%) were identified. Of these, 63 (56.3%) did not experience any current and lifetime DSM-III-R diagnoses, yielding a 12-month or lifetime prevalence rate of "pure" NT of 3.61%. This rate was much higher than any of the other psychiatric disorders in this sample. Compared with normal subjects, "pure" NT subjects had significantly higher SCL-90-R total and factor scores, experienced more psychosocial stress, and perceived less social support (P < .05 or .01). Compared with subjects with depression and anxiety disorders, "pure" NT cases reported significantly less SCL-90-R psychological symptoms (P < .05 or .01), but had a strikingly similar elevation in the somatization subscale score. These data suggest that NT is a distinctive clinical condition overlapping only partially with the other better recognized diagnostic entities. In view of its high prevalence and the salience of its impact on the health of those afflicted, it is imperative that concerted research efforts be made to further elucidate the temporal stability, natural course, and outcome of such a condition.
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PMID:An epidemiological study of neurasthenia in Chinese-Americans in Los Angeles. 929 16

Stress produces a reduction in the amplitude of some circadian rhythms. The neurochemical mechanisms underlying stress-induced changes in circadian rhythms are not known. To investigate a possible role of corticotropin-releasing factor (CRF) in this phenomenon, three related experiments were carried out: activity rhythms of male golden hamsters (10/14 hours light/dark entrained, lights on at 0800 h) were measured 1) following the intracerebroventricular administration of CRF (0.5, 1.0, 2.0, or 4.0 microg) at two different times of day, 2) following social stress (30-min resident-intruder confrontation), 3) and following the administration of the CRF-antagonist alpha-helical CRF9-41 (2.0 microg) prior to a 15-min resident-intruder confrontation. CRF produced a significant, dose-related decrease in circadian rhythm amplitude following administration in the morning hours, but not in the afternoon. CRF also induced transient increases in activity post injection concomitant with an activation of the hypothalamic-pituitary-adrenocortical (HPA) system. Stress similarly reduced the amplitude of activity patterns and stimulated the HPA system. The stress-induced depression of circadian rhythm amplitude was significantly attenuated following alpha-helical CRF9-41. These data suggest a role for CRF in the stress-related modulation of circadian locomotor rhythm amplitude.
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PMID:Effects of corticotropin-releasing factor on circadian locomotor rhythm in the golden hamster. 970 Sep 69

Although various experimental models of mental illness, such as anxiety and depression, have been developed, little attention has been paid to male psychogenic impotence. Since sociopsychological factors are presumed to play an important role in many cases of human impotence, an animal model of psychogenic impotence is needed to satisfy such validity. From an ethological viewpoint, we have recently developed new animal models for psychogenic impotence using sociopsychological manipulations, that is, social deprivation and social conflict. This review focused only on the methodology and the actions of drugs on such copulatory disorder induced by social stress. Possible brain mechanisms underlying stress-induced copulatory disorder were also considered.
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PMID:[New animal models for psychogenic impotence: an ethological approach to copulatory disorder induced by social stress]. 1002 88

Previous studies have shown that stressors modify endogenous opioid systems. However, the consequences of social stress on the function of endogenous opioid systems is not well documented. The present studies investigated the effect of rank and housing condition on response to SNC-80, a delta receptor agonist. Triad-housed rats were assessed for dominance status by their behavior and alteration in body weights. At 3 and 50 days, triad- and individually housed rats were injected with SNC-80 (35 mg/kg i.p.) or saline, and evaluated using a test battery consisting of open field behaviors, rectal temperature, analgesia, and air-puff-induced ultrasonic vocalizations. After 50 days of housing, plasma corticosterone, adrenal catecholamines, and the density of cyclic[D-penicillamine2-D-penicillamine2]enkephalin-stimu lat ed guanylyl 5'-[gamma[35S]thio]-triphosphate binding in the prefrontal cortex, the amygdala, nucleus accumbens, thalamus, arcuate, and median eminence were also determined. The first 24 h of triad housing resulted in loss of body weight in subdominant (betas and gammas) but not dominant alpha rats. SCN-80-induced hypothermia was smaller, and there was no depression of headpoke and locomotor behavior in the periphery and the center of the field of alpha rats, in contrast to subdominant and singly housed rats. Rank status did not influence SNC-80's analgesic effect or its inhibition of air-puff-induced ultrasonic vocalizations. Plasma corticosterone levels of alphas and gammas were lower compared with betas and singly housed rats. Agonist stimulation of delta receptor guanylyl 5'-[gamma[35S]thio]-triphosphate binding was lateralized in prefrontal cortex and amygdala, but not nucleus accumbens. Binding was highest in all brain areas of singly housed rats and lowest in the thalamus of beta and of gamma rats. Lateralized binding in amygdala, high locomotor activity, and sensory sensitivity correlated positively with greater sensitivity to SNC-80-induced depression in these measures. Higher binding in the right amygdala correlated with higher plasma corticosterone levels. These findings indicate that dominant rats displayed stimulant rather than depressant responses to delta-opioid activation. Therefore in rodents rank-related stress can alter responsiveness of the endogenous opioid system, and dominance can increase the excitatory effects of delta agonists.
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PMID:Effect of chronic social stress on delta-opioid receptor function in the rat. 1038 76

In order to investigate if HPA functioning is altered with age, the present study was conducted. Fifteen healthy elderly men (60-76 years; mean age 66.5 +/- 1.48 yrs.) and 12 younger adults (20-29 years; mean age 25.6 +/- 0.77 yrs.) collected salivary free cortisol profiles after awakening for basal HPA activity. Then, all subjects were exposed to the "Trier Social Stress Test" (TSST). This psychosocial stress protocol consists of a free speech and a mental arithmetic task of 13 minutes duration performed in front of an audience. Beside the assessment of endocrine and cardiovascular responses to the stressful task ratings of depression, mood and perceived stressfulness were obtained. Results show that younger and elderly men had similar morning cortisol profiles after awakening with both groups showing the expected rise after awakening (P=0.004). The TSST induced significant increases in ACTH, total plasma cortisol, saliva free cortisol, and heart rates (all P<0.0001). Regardless of age, both age groups showed comparable endocrine response patterns when confronted with the stressor. However, cardiovascular responses were significantly higher in younger men compared to elderly men (P=0.03). Catecholamine data revealed significant norepinephrine and epinephrine increases due to the stressor (both P<0.0001) with a trend toward elevated norepinephrine levels in elderly men (P=0.058). In sum, the investigated basal and response parameters of HPA functioning neither support the idea of a reduced resilience in healthy aged humans nor do they appear to strengthen assumptions derived from the so called "glucocorticoid cascade hypothesis".
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PMID:Psychosocial stress and HPA functioning: no evidence for a reduced resilience in healthy elderly men. 1093 84

This study examines how an extensive set of covariates identified in previous research--sociodemographics, social stressors, health status and psychosocial resources--influence the age-depression relationship. The analyses were based on data collected for the 1994 National Population Health Survey (N = 16,291) by Statistics Canada. Analyses were conducted using OLS regression for generalized distress and logistic regression for major depressive episode. The relationship between age and both outcomes was linear and negative after controlling for sociodemographics. Controlling for social stress reduced levels of depression among younger cohorts while controlling for poor health status reduced levels of depression among the elderly. Controlling for psychosocial resources generally reduced the level of depression among older cohorts, however, the results were mixed across outcomes. The inclusion of all covariates appears to negate the effects of one another in that the fully adjusted relationships between age and depression across both outcomes were not significantly different from their bivariate relationships.
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PMID:The effect of sociodemographics, social stressors, health status and psychosocial resources on the age-depression relationship. 1098 92

Depression is generally precipitated by stressful life events, which suggests that there could be differences in response to stress in individuals at risk for depression compared to normal subjects. To test this hypothesis, we compared individuals who scored high on ruminative coping, a risk factor for depression, to individuals low on ruminative coping. We used the Trier Social Stress Test (TSST), a mock job interview in front of a panel of judges, and collected saliva cortisol to assess neuroendocrine response. While we observed a clear effect of the stressor on saliva cortisol secretion, we observed no differences in this response between high and low ruminators. However, the task itself failed to cause a significant increase in rumination in either group, suggesting the task itself may not be optimal for testing the hypothesis. Finally, a modified version of the TSST in which the subjects were allowed a longer preparatory period resulted in a markedly diminished saliva cortisol response to the TSST.
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PMID:Effect of ruminations on the saliva cortisol response to a social stressor. 1116 94

The present study examines gender-related issues in the development of animal models of depression and anxiety disorders. Three main issues are discussed: (1) gender differences in the prevalence, etiology, and responses to treatments of neuropsychiatric disorders. An extensive literature reports that mood disorders are more frequent in women compared with men but the great majority of basic research has focused on male rodents as animal models; (2) sex-differences in behavior reflect both organizational and activational effects of steroid hormones, and should be considered in the conceptual frame of the evolutionary theory of sexual selection; (3) animal models of anxiety and depression. Social stress appears to be a good model to induce anxiety-like and depression-like responses, but a large discrepancy in the possibility of inducing social stress in the two genders exists. Reliable models of social stress in females are needed. The effects of social context, as a possible source of stress, on exploration and anxiety in male and female mice were investigated by taking into account the natural history and social behavior of this species. Mice housed individually for 7 days or with siblings were tested in a free-exploratory paradigm of anxiety (where test animals have a choice to stay in their home cage or to explore an open field). Individually housed females showed lower propensity for exploration and a higher level of anxiety compared with group-housed females. Individually housed males tended to show an opposite profile. Animal models may contribute to elucidating some aspect of neuropsychiatric disorders, but they require consideration of the natural life of the animal species studied and of their social behavior in an evolutionary perspective.
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PMID:Animal models of anxiety and depression: how are females different? 1137 78

This article offers a theoretical framework based on evolutionary thinking designed to clarify relationships between social stress and mental illness, including the origin of gender differences in vulnerability to stress. From a Darwinian perspective, stress is an interference with evolved behavioral strategies. Human behavior is organized around the pursuit of biological goals, and any social event that interferes with these evolved strategic goals may constitute a stressor. The response to such interference -- the stress response -- is made up of physiological, psychological and behavioral components. These components determine how individuals deal with those social events that were likely to reduce inclusive fitness in the ancestral environment. Evolved gender differences in commitment to goals play a role in determining individual differences in response to stressors. When a social stressor interferes with achieving a biological goal, its harmful impact will depend primarily on the importance of the goal to an individual, and the importance assigned to different goals by an individual does not depend exclusively on personal variables and cultural values. Two evolutionary theories are relevant to gender differences in vulnerability to social stress: sexual selection theory and life history theory. Clinical data from patients suffering from depression triggered by social stress are reviewed to test predictions derived from these theories.
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PMID:Gender differences in vulnerability to social stress: a Darwinian perspective. 1143 73

In the present study, we investigated whether synaptic plasticity changes in the hippocampus of depressive-like socially stressed rats could be reversed by chronic antidepressant treatment. To that end, rats were either defeated and subsequently individually housed or subjected to control treatment followed by social housing. After a period of at least 3 months, rats were either treated chronically with imipramine (20 mg/kg per day, per os for at least 3 months) or the solvent solution (i.e. water). Then, long-term potentiation and depression were measured in the CA1 region of the hippocampus in vitro. Chronic imipramine treatment partially restored the attenuated induction of long-term potentiation and suppressed the facilitation of long-term depression-induction in socially stressed rats. The altered synaptic plasticity after social stress is discussed in relation to cognitive deficits and hippocampal changes that are observed in depressive patients.
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PMID:Chronic imipramine treatment partially reverses the long-term changes of hippocampal synaptic plasticity in socially stressed rats. 1151 64


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