Introduction: Incidence of hospitalisations related to psychoactive substance intoxication (H-SPA) might have been differently impacted by the Covid-19 pandemic according to age-groups. This study aimed to describe (i) the incidence of H-SPA during and after the first 2020 lockdown in adults aged 18–29 years or 30+ then (ii) their characteristics specifically associated with the pandemic period by comparing 2020 with 2017–2019 baseline period. Material and methods: This historical cohort study was conducted in adults admitted to the University Hospital of Bordeaux with main or secondary diagnosis codes of intoxication with benzodiazepine, methadone, buprenorphine, codeine, morphine, heroin, cocaine, ecstasy and alcohol. Data were collected locally through the discharge database. Incidence and characteristics of H-SPA were described according to patients age, in 2020 before (01/01-16/03), during (17/03-10/05), and after the first lockdown (11/05-31/07). Results: Among the 5824 stays included over the study period, SPA most involved were alcohol and benzodiazepines. Compared to baseline, the decrease in H-SPA's incidence was more important in young adults (−40%; nbaseline = 450) in comparison to those aged 30+ (−18%; nbaseline = 1,101) during the pandemic period, especially during the lockdown compared to 2017 (−59%; n2017 = 145 vs − 35%; n2017 = 166) with far decrease in alcohol and ecstasy intoxications. Seriousness of hospitalization indications was increased regardless of age during the pandemic. Particularly in young adults, the proportion of suicides increased during lockdown compared to the baseline period (almost 50% vs 29%) and the proportion of accidents in context of intoxication (3.5 vs 0.7%) after lockdown. Discussion/Conclusion: The period following lockdown should be considered at risk for hospitalizations due to accident in context of SPA use. Strong decrease in the incidence of H-SPA in young adult during the lockdown highlights the health burden of recreational use of alcohol and ecstasy in this population and the need for prevention.Read less <