Our search strategy was designed to inform this Review and a second review to be published elsewhere relating to adherence to quarantine. We searched Medline, PsycINFO, and Web of Science. The full list of search terms can be found in the appendix. In brief, we used a combination of terms relating to quarantine (eg, “quarantine” and “patient isolation”) and psychological outcomes (eg, “psych” and “stigma”). For studies to be included in this Review, they had to report on primary research, be published in peer-reviewed journals, be written in English or Italian (as these are the languages spoken by the current authors), include participants asked to enter into quarantine outside of a hospital environment for at least 24 hours, and include data on the prevalence of mental illness or psychological wellbeing, or on factors associated with mental illness or psychological wellbeing (ie, any predictors of psychological wellbeing during or after quarantine). The initial search yielded 3166 papers, of which 24 included relevant data and were included in this Review. The screening process is illustrated in the figure.