Quetiapine effect on depressive-like behaviors, oxidative balance, and inflammation in serum of rats submitted to chronic stress.

Major depressive disorder (MDD) etiology is still not completely understood, and many individuals resist the traditional treatments. Chronic exposure to stressful events can contribute to development and progression and be involved in biological changes underlying MDD. Among the biological mechanisms involved, inflammatory changes and oxidative balance are associated with MDD pathophysiology. Quetiapine, a second-generation antipsychotic, induces a better therapeutic response in individuals refractory to traditional treatments. The main objectives of this research were as follows: to evaluate the effect of chronic mild stress (CMS) on depressive-like behaviors, oxidative stress, and inflammation in adult rats; to evaluate the possible antidepressant, antioxidant, and anti-inflammatory effects of quetiapine. The animals were submitted to CMS protocols. At the end of the CMS, the animals were submitted to a chronic treatment for 14 days with the following drugs: quetiapine (20 mg/kg), imipramine (30 mg/kg), and escitalopram (10 mg/kg). At the end of the treatments, the animals were evaluated in the open field tests, anhedonia (splash test), and forced swimming. The animals were euthanized after the behavioral tests, and serum samples were collected. Myeloperoxidase (MPO) activity and interleukin-6 (IL-6) levels were analyzed. CMS induced an increase in depressive-like behaviors, and quetiapine significantly reduced these behaviors. MPO activity and IL-6 levels increased in the serum of animals submitted to CMS. Quetiapine significantly reduced MPO activity and IL-6 levels. These results corroborate other evidence, indicating that chronic stress is a relevant phenomenon in the etiology of depression and suggesting that quetiapine induces an antidepressant effect because it reduces oxidative and inflammatory mechanisms.

Common mental disorders among medical students: systematic review and meta-analysis of Brazilian studies

ABSTRACT BACKGROUND: Common mental disorders (CMDs) have been correlated with consequences in different domains of life. OBJECTIVE: To summarize the prevalence rates of CMDs and factors associated with them among students at Brazilian medical schools. DESIGN AND SETTING: Systematic review and meta-analysis of studies developed in Brazilian medical schools. METHODS: In October 2021, searches were carried out in seven electronic databases, in Google Scholar and in reference lists. Observational studies reporting prevalence rates of CMDs among students at Brazilian medical schools were sought. Variables associated with CMDs arising from multivariate regression models were included in the synthesis. A meta-analysis was developed using a random-effects model and the risk of bias was assessed using an instrument developed from previous references. RESULTS: Fourteen original studies were included. The pooled prevalence rate of CMDs among undergraduate students at Brazilian medical schools was 43.3% (95% confidence interval = 38.9% to 47.6%; I2 = 87%; n = 3,927). Among the nine studies in which multivariate analyses were conducted, five showed risk associations between CMDs and medical school-related dissatisfactions, among which the desire to abandon the medical course can be highlighted (n = 3). In three studies, CMDs were associated with sleep indicators. CONCLUSION: Considering that the prevalence of CMDs among medical students is higher than in the general population, we recommend that Brazilian medical schools should give greater attention to this topic, and should enable expansion of care offerings relating to mental health. SYSTEMATIC REVIEW REGISTRATION: Prospective Register of Systematic Reviews (PROSPERO) database (CRD42020142184).