BACKGROUND: The objectives are to examine time trends in the prevalence of past year major depressive episode (MDE) among young adults, and to identify differences by occupational status comparing students, those employed, and those who are not in employment, education or training (NEET). METHODS: Data were drawn from the Health Barometer survey, a cross-sectional computer-assisted telephone interview survey on a national representative sample of residents of metropolitan France and conducted approximately every 5 years. The surveys relied on the Composite International Diagnostic Interview-Short Form to determine the presence of DSM-IV past-year major depressive episode. Data from the 2005, 2010, 2017, and 2021 surveys were pooled and respondents aged 18 to 25 were selected (n = 7556) and categorized based on their occupational status: students, those employed, and NEET. RESULTS: Overall, significant differences in the prevalence of MDE was observed by occupational status: NEET had the highest rate (18.5 %) followed by students (14.3 %) and those employed (11.0 %). The prevalence of MDE among young adults was 10.1 % in 2005, 9.7 % in 2010 and 11.3 % in 2017, reflecting a stable prevalence between 2005 and 2017. The prevalence then nearly doubled in 2021, with 20.9 % of MDE, with a significant increase of 9.6 points between 2017 and 2021. LIMITATIONS: No assessment of lifetime psychopathology. CONCLUSIONS: The prevalence of major depression among young adults significantly increased between 2005 and 2021, those at greatest risk are females and those not in employment, education or training. The contribution of pandemic-related factors may be elucidated in future national health surveys.