Mental health trajectories before, during, and after the COVID-19 pandemic among patients attending a psychosomatic internal medicine clinic in Japan: A retrospective quantitative study

The coronavirus disease 2019 (COVID-19) pandemic has exacerbated anxiety and depression globally, particularly among individuals with mental health conditions and chronic illnesses. However, the extent to which these mental health effects have persisted following the pandemic remains unclear. This study examined changes in mental health before, during, and after the COVID-19 pandemic among first-time patients attending a psychosomatic internal medicine clinic in Japan. The legal reclassification of COVID-19 to "Class5" status under Japan's Infectious Diseases Control Law, which took effect on May 8 2023, serves as the benchmark marking the beginning of the post-pandemic era, designated as the beginning of the post-pandemic period. The General Health Questionnaire (GHQ)-30, State-Trait Anxiety Inventory, and Center for Epidemiologic Studies Depression Scale (CES-D) were used to assess general mental health, state and trait anxiety, and depressive symptoms, respectively. Participants were classified into pre-pandemic (n = 87), during-pandemic (n = 322), and post-pandemic (< 1 year: n = 75 and 1-2 years: n = 68) groups. The Mann-Whitney U test was used to compare mental health outcomes across the study periods. A total of 552 participants completed the survey (237 men and 315 women; mean age: 44.57 ± 19.56 years). Within 1 year after the pandemic, GHQ total mean scores, sleep disturbance, anxiety and dysphoria, and CES-D mean scores were significantly higher than those in the pre-pandemic group (GHQ total: 16.32 vs 13.57, P = .015; sleep disturbance: 3.70 vs 2.65, P < .001; anxiety and dysphoria: 3.14 vs 2.35, P = .016; CES-D: 26.53 vs 21.39, P = .005). Sleep disturbance scores were also significantly higher within 1 year after the pandemic than during the pandemic (3.70 vs 3.19, P = .015) but were significantly lower in the 1 to 2 years post-pandemic group than in the within-one-year post-pandemic group (2.65 vs 3.70, P = .022). These findings suggest that symptoms of anxiety, depression, and sleep disturbance persisted during the early post-pandemic period but gradually improved over time. Particularly, sleep disturbance remained one of the most persistent mental health concerns, highlighting the importance of continued attention to the mental health of patients with psychosomatic disorders following the COVID-19 pandemic.