BackgroundDepression is an important contributor to the global burden disease that affects people of communities all over the world. With high level of demands in academics and psychosocial pressure, medical students during their course of training tend to become depressed, leading to problems later in professional life and compromising patient care. In Cameroon, there is lack of data on the prevalence of depression and its impact on medical students. To determine the prevalence and predisposing factors associated with depression among medical students in Cameroon (preclinical and clinical). We also evaluated the impact of depression on self-reported academic performance.MethodsA cross sectional study was carried out in all 4 state medical schools in 4 different regions from December 2015 to January 2016. Diagnosis of depression, major depression and its associated factors were assessed using the 9-Item-Patient Health Questionnaire (PHQ-9) and a structured questionnaire respectively. We included 618 medical students (response rate: 90.4%).ResultsAbout a third of them (30.6%, 95% CI: 22.8–36.7) were found to have major depressive disorder (PHQ Score ≥ 10). With regards to the severity of depression, 214 (34.6%), 163 (26.4%), 21 (3.4%), and 5 (0.80%) students were classified as having mild, moderate, moderately severe and severe depression respectively. The presence of a chronic disease (OR: 3.70, 95% CI: 1.72–7.94, p = 0.001), major life events (OR: 2.17, 95%CI: 1.32–3.58, P = 0.002), female gender (OR: 1.59, 95% CI: 1.06–2.37, p = 0.024) and being a student at the clinical level (OR: 4.26, 95% CI: 2.71–6.71, p < 0.001) were independently associated with depression. There was no association between depression and self-reported academic performance, (OR: 1.2, 95% CI: 0.9–1.7, p = 0.080).ConclusionThe prevalence of major depressive disorders among medical students in Cameroon is high and is associated with the presence chronic disease, major life events, female gender and being a student at the clinical level. So we recommend clinicians attending to medical students with demographic features suggestive of greater risk of depression, to make an in depth investigation on the possible presence of depression. Despite this high prevalence of major depression among medical students, it was not associated with self-reported academic performance.