Wistar Kyoto Rats Display Anhedonia In Consumption but Retain Some Sensitivity to the Anticipation of Palatable Solutions

Uncertainties exist about prevalence and correlates of major depressive disorder (MDD). To present nationally representative data on prevalence and correlates of MDD by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria, and on study patterns and correlates of treatment and treatment adequacy from the recently completed National Comorbidity Survey Replication (NCS-R). Face-to-face household survey conducted from February 2001 to December 2002. The 48 contiguous United States. Household residents ages 18 years or older (N = 9090) who responded to the NCS-R survey. Prevalence and correlates of MDD using the World Health Organization's (WHO) Composite International Diagnostic Interview (CIDI), 12-month severity with the Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR), the Sheehan Disability Scale (SDS), and the WHO disability assessment scale (WHO-DAS). Clinical reinterviews used the Structured Clinical Interview for DSM-IV. The prevalence of CIDI MDD for lifetime was 16.2% (95% confidence interval [CI], 15.1-17.3) (32.6-35.1 million US adults) and for 12-month was 6.6% (95% CI, 5.9-7.3) (13.1-14.2 million US adults). Virtually all CIDI 12-month cases were independently classified as clinically significant using the QIDS-SR, with 10.4% mild, 38.6% moderate, 38.0% severe, and 12.9% very severe. Mean episode duration was 16 weeks (95% CI, 15.1-17.3). Role impairment as measured by SDS was substantial as indicated by 59.3% of 12-month cases with severe or very severe role impairment. Most lifetime (72.1%) and 12-month (78.5%) cases had comorbid CIDI/DSM-IV disorders, with MDD only rarely primary. Although 51.6% (95% CI, 46.1-57.2) of 12-month cases received health care treatment for MDD, treatment was adequate in only 41.9% (95% CI, 35.9-47.9) of these cases, resulting in 21.7% (95% CI, 18.1-25.2) of 12-month MDD being adequately treated. Sociodemographic correlates of treatment were far less numerous than those of prevalence. Major depressive disorder is a common disorder, widely distributed in the population, and usually associated with substantial symptom severity and role impairment. While the recent increase in treatment is encouraging, inadequate treatment is a serious concern. Emphasis on screening and expansion of treatment needs to be accompanied by a parallel emphasis on treatment quality improvement.

Stress is associated with the onset and severity of several psychiatric disorders that occur more frequently in women than men, including posttraumatic stress disorder (PTSD) and depression. Patients with these disorders present with dysregulation of several stress response systems, including the neuroendocrine response to stress, corticolimbic responses to negatively valenced stimuli, and hyperarousal. Thus, sex differences within their underlying circuitry may explain sex biases in disease prevalence. This review describes clinical studies that identify sex differences within the activity of these circuits, as well as preclinical studies that demonstrate cellular and molecular sex differences in stress responses systems. These studies reveal sex differences from the molecular to the systems level that increase endocrine, emotional, and arousal responses to stress in females. Exploring these sex differences is critical because this research can reveal the neurobiological underpinnings of vulnerability to stress-related psychiatric disorders and guide the development of novel pharmacotherapies.

Depression is currently among the top five leading causes of the global burden of disease. Chronic unpredictable mild stress (CUMS) is currently the most commonly used, reliable, and effective rodent model of depression. However, for unclear reasons, this protocol is often difficult to reproduce in different laboratories. We performed a meta-analysis of studies that used the CUMS paradigm to evaluate depressive-like behavior in rodents. We sought to identify strain-dependent susceptibility to stress based on the development of one of the main end points of the model, "anhedonia." The meta-analysis indicated that the CUMS protocol is a robust animal model of depression and is strongly associated with anhedonic behavior in rodents. However, high heterogeneity was found in the single subgroup analysis, which was attributable to modification of the CUMS and sucrose preference protocols. This may explain difficulties in reproducing stress protocols by different research groups.