The impact of the COVID-19 public health social measures (PHSM) on health behaviours is poorly understood. We aimed to identify factors associated with changes in alcohol and tobacco consumption during the strictest period of PHSM ‘lockdown’. 

Methods: Logistic regression analysis was conducted using secondary data from the Central Statistics Office Social Impact Survey collected during the first lockdown in Ireland (23 April– 1 May 2020). 

Results: Of the 1362 (33.8%) individuals that responded to the survey, 80.6% were current drinkers and 26.0% were smokers. The majority of smokers (60.9%) and drinkers (60.6%) reported no change in consumption. However, 30.5% of smokers and 22.2% of drinkers reported increased consumption. 

Being concerned about household stress from confinement [adjusted odds ratio (aOR) 1.9, 95% confidence interval (CI) 1.3–2.9, P ¼0.002], working from home (aOR 2.1, 95 CI 1.4–3.3, P <0.001) and urban living (aOR 2.0, 95 CI 1.5–2.9, P <0.001) were associated with increases in alcohol consumption. Feeling very nervous (aOR 2.2, 95% CI 1.2–4.0, P¼0.009), feeling downhearted/depressed (aOR 2.4, 95% CI 1.3–4.4, P¼0.004), being concerned about someone else’s health (aOR 2.0, 95% CI 1.1–3.9, P¼0.031), working from home (aOR 2.3, 95% CI 1.0–5.3, P ¼0.046) and increases in alcohol consumption (aOR 3.6, 95% CI 1.7–7.7, P ¼0.023) were associated with increases in tobacco consumption. 

Conclusion: A mixed picture was evident in terms of changes in consumption among current smokers and drinkers. Increased consumption was more commonly reported than reductions. Increased consumption was associated with psychological distress and socio-economic factors. Policies and services should consider a response to widening inequalities in harmful consumption.