We assessed depression in 72 patients with Alzheimer’s disease (AD) who live in retirement homes during the COVID-19-related lockdown. We invited caregivers of 72 patients with AD who live in retirement homes to rate depression in the patients both before and during the lockdown. Analysis demonstrated increased depression in the patients during the lockdown. We attribute this increased depression to the restrictive measures on activities, visits, and physical contact between patients with AD and family members during the lockdown.