This editorial discusses the psychological effects of isolation and quarantine in terms of both the SARS-CoV-2 (COVID-19) pandemic and previous epidemics in the past 20 years. Although much of the literature is based on healthcare settings, there is emerging evidence from home or hotel quarantine, particularly concerning international travellers. Regardless of setting, depression, anxiety, anger and stress-related disorders are especially common but can vary according to demographic features and the characteristics of quarantine. Psychological effects may be minimised by clear and consistent advice from authorities, adequate supplies to meet basic needs, and minimising both the duration and the associated financial burden. There should also be adequate protection from possible infection and thus the resulting fear of contracting COVID-19 while in quarantine.