Objective: To study prevalence and associated factors of depression in medical students at Faculty of Medicine, Vajira Hospital.

Materials and methods:This was a cross-sectional survey study in medical students from year 1 to year 6. The survey included general demographic data and factors associated with depression. Patient Health Questionnaire-9 (PHQ-9) Thai version was used to assess depressive symptoms. Statistical tools including descriptive statistics, chi-square and multiple logistic regression, were used.

Results: A total of  298 medical students from year 1 to year 6 were included in the study. One hundred and fifty-five (52%) subjects were female.  Prevalence of depression was 91(30.5%). Suicidal ideation was 12.8%. Prevalence of depression and suicidal ideation were highest in fourth year medical students which were 37.5% and 20.8%, respectively. In multivariate analyses factors associated with depression were pessimism; sometimes [Odds ratio(OR)= 6.48; 95% confident interval (CI)] = 1.83 – 22.96; p=0.004] and often (OR=8.86; 95%CI = 1.34 – 58.31; p=0.023), family relationship (OR=8.07;95%CI = 2.49 – 26.09; p<0.001), inadequate sleep (OR=3.35;95%CI = 1.71 – 6.56; p<0.001) and psychological abuse (OR=2.55;95%CI = 1.43 – 4.56; p=0.001).

Conclusion: Prevalence of depression in medical student of Urban University was high at 30.5%. Associated factors with depression were pessimism, family relationship, inadequate sleep and psychological abuse. Surveillance and early detection are indicated to prevent further impact.