パンデミック中の新型コロナウイルス感染症（COVID-19）関連心的外傷後ストレス、孤独感、および不安：4回の調査によるパネル研究

Collective health crises, such as the COVID-19 pandemic, pose significant psychosocial challenges that may increase vulnerability to posttraumatic stress (PTS). The present longitudinal study examined the associations between COVID-19-related PTS and two psychosocial vulnerability factors: loneliness and COVID-19-related worries. Data were collected from a sample of 747 adults in the United States (U.S.), recruited via Amazon Mechanical Turk (MTurk), with follow-ups conducted at approximately 6-month intervals beginning in March 2020. Retention rates across the four waves were as follows: Time 2 (T2) = 458, Time 3 (T3) = 445, and Time 4 (T4) = 432. Cross-lagged panel analyses indicated that loneliness consistently predicted subsequent increases in PTS symptoms across waves, whereas the reverse pathways from PTS to loneliness were not significant. Both loneliness and PTS measured at Time 1 (T1) significantly predicted COVID-19-related worries at T2; however, these effects did not persist in subsequent waves. Additionally, a delayed effect was observed in which COVID-19-related worries at T2 significantly predicted increased loneliness at T3, although this association was not observed at later time points. These findings highlight the enduring role of loneliness in the development of pandemic-related PTS and suggest that both loneliness and PTS contribute to elevated worry during the early stages of widespread infectious disease outbreaks. Early interventions targeting loneliness may be critical for reducing long-term psychological distress and enhancing resilience in the context of pandemics and similar public health emergencies.