Resilience, sleep quality and morningness as mediators of vulnerability to depression in medical students with sleep pattern alterations.

The medical career is considered highly stressful, especially during internships when academic and clinical demands, combined with changes in sleep patterns, increase students' likelihood to develop depression. Resilience, which is considered as opposite vulnerability to stress and, along with another protective factor, namely morningness, may cause a student to be less reactive to stimuli and, therefore, less prone to depression. The objective of this study was to evaluate the role of resilience and morningness facing to sleep quality and main risk factors, on the development of depression symptoms in a group of students with sleep pattern alterations. To this end, an observational and longitudinal study was performed with 30 undergraduate interns, with an average age of 22.63 years (SE ± 0.13), 33% men and 67% women. A survey was conducted in three different times during the year of internship: at the beginning (T1), in the middle (T2) and the end (T3). The instruments were the Brief Resilience Scale, Composite Scale of Morningness, Pittsburgh Sleep Quality Index and Patient Health Questionnaire. The path analysis examined the roles of morningness, sleep quality and resilience as potential mediators between family history of depression and depression symptoms at different times. The results showed that resilience had a protective effect on depression symptoms at T2 (β = -0.18, p < 0.05) and with greater power at T3 (β = -0.41, p < 0.05), as did morningness, although less strongly, on the symptoms at T3 (β = -0.13, p < 0.05). A relationship between these two mediating variables was also observed (β = 0.30, p < 0.05). The initial sleep quality had an effect on the increase of depression symptoms at T1 (β = 0.61, p < 0.05) and T3 (β = 0.21, p < 0.05), while family history of depression had a direct effect on the measures of depression at T2 (β = 0.49, p < 0.05) and T3 (β = 0.19, p < 0.05). Aside from personal risk factors, it is possible to conclude that the levels of resilience, morningness and sleep quality manifested by students at the beginning of their internship may explain the decrease in depression symptoms at the end of the course.