Major depressive disorder in Mexican medical students and associated factors: A focus on current and past abuse experiences.

BACKGROUND: Major depressive disorder (MDD) is highly prevalent among medical students (MS). Abuse experiences, as well as stress, are among the factors associated with MDD. However, their association with MDD in MS has been scarcely addressed. METHODS: A cross-sectional study design was used to evaluate the association between MDD and possible risk factors, focusing on current and past abuse experiences inside and outside the academic setting in a large representative MS sample (n = 1,068) using self-report instruments to assess MDD (PHQ-9) and perceived academic stress levels during exam season. RESULTS: Depressive symptom severity directly correlates with levels of perceived academic stress. The prevalence of MDD was 16.2%. A history of emotional abuse during childhood or adolescence, as well as most types of current abuse were associated with MDD. Multiple logistic regression analysis showed that current emotional abuse outside school had the strongest association with MDD in MS, followed by a personal history of depression and suicide attempt, a family history of depression, and perceived academic stress levels. LIMITATIONS: Cross-sectional design, participants represent a specific population, and other variables that could be associated with MDD: comorbid psychiatric disorders, current antidepressant treatment and protective factors (resilience and health-promoting coping strategies) were not evaluated. CONCLUSIONS: MDD is strongly associated with several risk factors that include most types of current and past abuse experiences. Timely identification of individuals at-risk will be critical to establish preventive strategies to limit the impact of MDD in MS and offer prompt therapeutic alternatives when needed.

The association between chronotype and perceived academic stress to depression in medical students.

Depression is a multifactorial illness that is highly prevalent among medical students (MS). Chronotypes, which reflect circadian preference in humans, as well as academic stress have been associated with depression in different populations. However, it is not known how chronotype and stress might alone or in combination, associate with depression in MS. Thus, we aimed to evaluate the association between stress, chronotype and depression in MS. In a cross-sectional study, we evaluated a total of 1068 medical students from a public Medical School in Mexico City. The Patient Health Questionnaire-9 (PHQ-9) was used to evaluate depressive symptom severity and the presence of a current depressive episode with a cutoff score of 10 or higher. The Morning-Evening Questionnaire (MEQ) was used to establish chronotype and the Academic Stress Inventory was used to measure perceived academic stress (PAS). We observed that depressive symptom severity was higher in non-morning chronotypes and moderate/severe PAS groups. A factorial ANOVA showed an association between PAS groups and depressive symptom severity. Linear regression showed an association between depressive symptom severity and variables such as PAS scores (p = 0.001), family history of depression (p = 0.001), gender (p = 0.001) and academic year (p = 0.029). Logistic regression analysis showed that evening chronotype (OR: 2.3, 95% CI: 1.2-4.3, p = 0.01) and severe PAS (OR: 4.4, 95% CI: 2.8-7.0, p = 0.0001) were associated with depression. Further, MS with the combination of severe PAS and morning (OR: 5.9, 95% CI: 1.6-22.2, p = 0.01), intermediate (OR: 7.5, 95% CI: 2.3-24.4, p = 0.001) or evening (OR: 10.6, 95% CI: 2.8-40.0, p = 0.001) chronotypes showed a greater association with depression than any PAS or chronotype group alone. Being female, perceiving restricted or limited economic resources, having severe scores of academic stress, and evening chronotype were associated with an increased probability to suffer a current depressive episode. Collectively, these results show that chronotype and PAS are factors associated with depression in MS, and when combined promote this association. Our results might aid in early identification of MS susceptible to depression. Future research could focus on the implementation of simple, low cost preventive strategies, such as chronotype-oriented academic schedules.