title: The association between chronotype and perceived academic stress to depression in medical students.
abstract: 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.
authors: a Departamento de Psiquiatría y Salud Mental, Facultad de Medicina , UNAM , DF , México.|b Division of Bipolar Disorder Research, Department of Psychiatry and Behavioral Neuroscience, College of Medicine , University of Cincinnati, Cincinnati , OH , USA.
authors: Francisco
authors: F
authors: Romo-Nava
authors: a Departamento de Psiquiatría y Salud Mental, Facultad de Medicina , UNAM , DF , México.
authors: Silvia A
authors: SA
authors: Tafoya
authors: a Departamento de Psiquiatría y Salud Mental, Facultad de Medicina , UNAM , DF , México.
authors: Joaquín
authors: J
authors: Gutiérrez-Soriano
authors: c Servicios de Atención Psiquiátrica, Secretaría de Salud, México , DF México.
authors: Yanik
authors: Y
authors: Osorio
authors: a Departamento de Psiquiatría y Salud Mental, Facultad de Medicina , UNAM , DF , México.
authors: Pilar
authors: P
authors: Carriedo
authors: a Departamento de Psiquiatría y Salud Mental, Facultad de Medicina , UNAM , DF , México.
authors: Bárbara
authors: B
authors: Ocampo
authors: d Departamento de Salud Pública de la Universidad Nacional Autónoma de México (UNAM) , Unidad de Medicina Familiar No. 1, Instituto Mexicano del Seguro Social, DF , México.
authors: Rosa I
authors: RI
authors: Bobadilla
authors: a Departamento de Psiquiatría y Salud Mental, Facultad de Medicina , UNAM , DF , México.
authors: Gerhard
authors: G
authors: Heinze
mesh_terms: D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D003863:Depression / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D010465:Perception / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D013315:Stress, Psychological; D013337:Students, Medical / Q000523:psychology*; D011795:Surveys and Questionnaires
keywords: Chronotypes; academic stress; depression