Changes in Psychological Distress During the COVID-19 Pandemic in Japan: A Longitudinal Study

This longitudinal study aimed to examine the changes in psychological distress of the general public from the early to community-transmission phases of the COVID-19 pandemic and to investigate the factors related to these changes.

An internet-based survey of 2,400 Japanese people was conducted in two phases: early phase (baseline survey: February 25-27, 2020) and community-transmission phase (follow-up survey: April 1-6, 2020). The presence of severe psychological distress (SPD) was measured using the Kessler's Six-scale Psychological Distress Scale. The difference of SPD percentages between the two phases was examined. Mixed-effects ordinal logistic regression analysis was performed to assess the factors associated with the change of SPD status between the two phases.

Surveys for both phases had 2,078 valid respondents (49.3% men; average age, 50.3 years). In the two surveys, individuals with SPD were 9.3% and 11.3%, respectively, demonstrating a significant increase between the two phases (P = 0.005). Significantly higher likelihood to develop SPD were observed among those in lower (ie, 18,600-37,200 United States dollars [USD], odds ratio [OR] 1.95; 95% confidence interval [CI], 1.10-3.46) and the lowest income category (ie, <18,600 USD, OR 2.12; 95% CI, 1.16-3.86). Furthermore, those with respiratory diseases were more likely to develop SPD (OR 2.56; 95% CI, 1.51-4.34).

From the early to community-transmission phases of COVID-19, psychological distress increased among the Japanese. Recommendations include implementing mental health measures together with protective measures against COVID-19 infection, prioritizing low-income people and those with underlying diseases.