AbstractObjective:Social distancing to limit COVID-19 transmission has led to extensive lifestyle changes, including for people with dementia (PWD). The aim of this study, therefore, was to assess the impact of lockdown on the mental health of PWD and their carers.Methods:Forty-five carers of PWD completed a telephone interview during the baseline assessment of the SOLITUDE study to gather information on life conditions and changes in symptoms of PWD during lockdown. Associations between changes in symptoms of PWD and carers’ concerns and mental health were investigated.Results:About 44% of carers experienced anxiety and irritability and reported changes in behavioural and cognitive symptoms in PWD. These changes were associated with worse carers’ mental health and concerns about faster disease progression (χ² = 13.542, p < 0.001).Conclusion:COVID-19-related social isolation has had a negative impact on patients’ and carers’ mental health. Potential long-term neurocognitive consequences require further investigation.