Physical activity, smoking, alcohol consumption and depressive symptoms among young, early mature and late mature people: A cross-sectional study of 76,223 in China

•The prevalence of clinical depressive symptoms was different among people with different brain maturity; the prevalence was highest among early mature participants.•Smoking and moderate alcohol consumption were protective factors for the mental health of young people and early mature participants.•Education was a protective factor for mental health in late mature adults, while excessive alcohol consumption was a risk factor.