BackgroundRates of diseases and death from tobacco smoking are substantially higher among those with a mental health condition (MHC). Vaping can help some people quit smoking, but little is known about vaping among people with MHCs or psychological distress. We assessed the prevalence and characteristics (heaviness, product type) of smoking and/or vaping among those with and without a history of single or multiple MHC diagnoses and with no, moderate or serious psychological distress.MethodsData from 27,437 adults in Great Britain surveyed between 2020 and 2022. Multinomial regressions analysed associations between smoking, vaping and dual use prevalence, smoking/vaping characteristics and (a) history of a single or multiple MHC and (b) moderate or serious psychological distress, adjusted for age, gender, and socioeconomic status.ResultsCompared with people who had never smoked, those who currently smoked were more likely to report a history of a single (12.5% vs 15.0%, AOR=1.62, 95% CI=1.46–1.81,p<.001) or multiple MHCs (12.8% vs 29.3%, AOR=2.51, 95% CI=2.28–2.75,p<.001).Compared with non-vapers, current vapers were more likely to report a history of a single (13.5% vs 15.5%, AOR=1.28, 95% CI=1.11–1.48,p<.001) or multiple MHCs (15.5% vs 33.4%, AOR=1.66, 95% CI=1.47–1.87,p<.001). Dual users were more likely to report a history of multiple MHCs (36.8%), but not a single MHC than exclusive smokers (27.2%) and exclusive vapers (30.4%) (allp<.05). Similar associations were reported for those with moderate or serious psychological distress.Smoking roll-your-own cigarettes and smoking more heavily, were associated with a history of single or multiple MHCs. There were no associations between vaping characteristics and a history of MHCs. Frequency of vaping, device type and nicotine concentration differed by psychological distress.ConclusionsSmoking, vaping and dual use were substantially higher among those with a history of MHC, especially multiple MHC, and experiencing past month distress than those not having a history of MHC or experiencing past month distress respectively. Analysis used descriptive epidemiology and causation cannot be determined.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12916-023-02890-y.