Social networks, loneliness, purpose in life, and psychological distress after the 2024 Noto Peninsula earthquake: a community-based cross-sectional survey and structural equation modeling study

Post-disaster psychological distress may be shaped not only by acute disaster exposure but also by evolving recovery-related and psychosocial conditions. This study examined factors associated with serious psychological distress (SPD) and the interrelationships between social networks, loneliness, purpose in life, and psychological distress among residents affected by the 2024 Noto Peninsula earthquake and subsequent heavy rainfall disaster. We conducted a secondary analysis of the Noto Peninsula Earthquake and Heavy Rainfall Disaster Survivor Health Survey, conducted in Ishikawa Prefecture, Japan, between January and February 2025. After excluding duplicate records, data from 16,296 adult respondents were included. SPD was defined as a K6 total score of 13 or higher. Multivariable logistic regression was used to examine factors associated with SPD, and structural equation modeling was used to examine psychosocial pathways linking social networks, loneliness, purpose in life, and psychological distress. In the complete-case logistic regression analysis ( n = 9,264), higher loneliness was associated with greater odds of SPD, whereas higher purpose in life was associated with lower odds of SPD. Current housing type and several health-related, behavioral, socioeconomic, disaster reminder-related, and psychosocial factors were also associated with SPD, whereas acute disaster exposure variables, including indicators of earthquake- and heavy rainfall-related damage, were not independently associated after adjustment. In the structural equation model ( n = 12,271), stronger social networks were associated with lower loneliness and higher purpose in life. Loneliness was positively associated with psychological distress, whereas purpose in life was inversely associated with psychological distress. Social networks were indirectly associated with lower psychological distress through lower loneliness and higher purpose in life, while showing a small positive direct association after accounting for these subjective psychosocial factors. During prolonged recovery in the context of compound disaster, mental health needs may be shaped by current living conditions and psychosocial states as well as initial disaster exposure. Post-disaster assessment and support strategies should distinguish between structural social networks, subjective loneliness, and purpose in life, and should consider how survivors experience and assign meaning to their social ties during recovery.