Persistence of Mental Health Deterioration Among People Living Alone During the COVID-19 Pandemic: A Periodically-repeated Longitudinal Study.

Background: This longitudinal study aimed to investigate how psychological distress levels changed from early to middle phases of the new coronavirus (COVID-19) pandemic depending on the living arrangements of individuals.

Methods: An internet-based, longitudinal survey of 2,400 Japanese people was conducted every 5-6 weeks between February 2020 and January 2021. The presence of severe psychological distress (SPD) was measured using the Kessler's psychological distress scale. Living arrangements were classified into two groups (ie, living alone or living with others). Mixed-effects logistic regression analysis was performed to assess whether changes in SPD status were different depending on living arrangements.

Results: Of 2,400 respondents, 446 (18.5%) lived alone. Although the proportion of SPD in both individuals living alone and those living with others increased to the same extent in the early phase of the pandemic, the distress levels decreased after the early phase of the pandemic in the group living with others, compared with the group living alone, for which SPD remained high. The odds ratio (OR) of developing SPD in interaction term with survey phases tended to be higher among those who lived alone than those who lived with others in Phase 6 (OR 1.89; 95% confidence interval [CI], 0.99-3.64) and Phase 7 (OR 1.88; 95% CI, 0.97-3.63).

Conclusion: During the COVID-19 pandemic, those living alone are persistently at a higher risk of SPD compared to those living with others. Effective countermeasures targeting those living alone, such as enhancing online communication or providing psychological therapies, are essential.