Medical student depression and its correlates across three international medical schools

BACKGROUND Medical students have high rates of depression, anxiety, and burnout that have been found to affect their empathy, professional behaviors, and performance as a physician. While studies have examined predictors for burnout and depression in the United States (US), no study, to our knowledge, has compared depression in medical students cross-culturally, or has attempted to examine the effect of factors influencing rates including burnout, exercise, stress, unmet mental health needs, and region. AIM To examine rates of depression in three international cohorts of medical students, and determine variables that may explain these differences. METHODS Convenience samples of medical students from three countries (US, China, and a Middle Eastern country whose name remains anonymous per request from the school) were surveyed in this observational study. Using the Patient Health Questionnaire-2 (PHQ-2) and a modified Maslach Burnout Inventory, depression and burnout were examined among medical students from the three cohorts (n = 473). Chi-square test and analysis of variance were used to examine differences in demographics, behavioral, and psychological variables across these three schools to identify potentially confounding descriptive characteristics. Analysis of covariance compared depression and the emotional exhaustion component of burnout identified through Principal Component Analysis across countries. Multiple linear regression was used to analyze the impact of demographic, behavioral, and psychological variables on screening positive for depression. RESULTS Medical students from the Middle Eastern country had the highest rates of positive depression screens (41.1%), defined as a PHQ-2 score of ≥ 3, followed by China (14.1 %), and then the US (3.8%). More students in the Middle Eastern school had unmet mental health needs (50.8%) than at the medical school in China (34.8%) or the school in the US (32.8%)(Pearson chi-square significance < 0.05). Thus, PHQ-2 scores were adjusted for unmet mental health needs;however, the Middle Eastern country continued to have the highest depression. Adjusting for PHQ-2 score, medical students from the US scored the highest on emotional exhaustion (a measure of burnout). Demographic variables did not significantly predict medical student depression;however, lack of exercise, unmet mental health needs, stress, and emotional exhaustion predicted nearly half of depression in these cohorts. In comparison to the US, coming from the Middle Eastern country and China predicted higher levels of depression. CONCLUSION Depression rates differ in three international cohorts of medical students. Measured factors contributed to some observed differences. Identifying sitespecific prevention and intervention strategies in medical student mental health is warranted.

Viologens-based redox mediators with tunable HOMO–LUMO energy gap for highly effective hydrogen peroxide electrosynthesis

In comparison with the developing nano-carbon catalysts,some small organic molecules are also emerging as catalysts with typical features,however,their working mechanism is still unclear.Here,we synthesized a series of viologen-based heterogeneous catalysts with the same molecular skeleton but different substituent groups through anion exchange engineering.These viologen-based molecules were used as a model catalyst to investigate the underlying structure–function relationship for small molecules-based H_(2)O_(2) electrosynthesis.Differing from the commonly reported carbon-based electrocatalysts,viologens can produce H_(2)O_(2) in a synergistic manner,which means that viologens can not only directly catalyze oxygen reduction but also serve as a redox mediator.We found that the ring current and H_(2)O_(2) selectivity of viologens deliver an increasing trend with the increase of the alkyl chain length of alkyl-substituted viologens and further increase when using benzyl as the substituent group.As a result,a benzyl-substituted viologen(BV)delivers the best electrocatalytic performance among the samples,including the highest H_(2)O_(2) selectivity of 96.9%at 0.6 V and the largest ring current density of about 13.6 mA·mmol-1.Furthermore,density functional theory(DFT)calculations disclose that the carbon atoms bonded with positively charged N are the active sites and the small highest occupied molecular orbital(HOMO)–lowest unoccupied molecular orbital(LUMO)energy gap of BV is beneficial to the synergistic mechanism for H_(2)O_(2) production.This work sheds new insight into the efficient H_(2)O_(2) production in a synergistic manner for small molecules-based electrocatalysts.