Psychological and somatic distress profiles in young adults in and out of conflict settings: a cluster-based analysis of three population-based studies in Ukraine and Switzerland

Background Young adulthood is a developmental period characterized by major life transitions and increased exposure to stress, during which vulnerability to psychological and somatic symptoms may be heightened. These symptoms frequently co-occur, posing challenges for diagnostic and treatment approaches. Despite the mental and physical symptom burden among young adults, population-based data on symptom patterns in this age group remains sparse. This study investigates psychological and somatic symptom patterns among young adults in three populations with differing socio-geographic and war-related context: young adults in Switzerland, Ukrainians who fled to Switzerland, and Ukrainians living in Ukraine. Methods We analyzed cross-sectional baseline data from the Mental Health Assessment of the Population (MAP) studies, where we enrolled randomly selected young adults aged 18–24 from Switzerland, Ukrainian refugees in Switzerland, and Ukrainians residing in regions with different degrees of proximity to active war zones. Participants completed standardized self-reported screening instruments assessing depressive symptoms (PHQ-9), anxiety symptoms (GAD-7), trauma-related stress symptoms (PCL-5), and somatic symptoms (PHQ-15). Descriptive statistics were calculated, and correlations between symptom domains were examined using Spearman correlations. K-means clustering was conducted separately in each subsample to characterize patterns of psychological and somatic symptom severity, with the number of clusters selected using the gap statistic. Results The baseline sample comprised n = 142 participants in MAP-Z (ZH), n = 102 in MAP-Z (UA), and n = 1,176 in the MAP-U subgroup. Complete PHQ-9, GAD-7, PCL-5, and PHQ-15 scores were available for 1,181 participants included in the cluster analyses (Switzerland: n = 127; Ukrainian refugees in Switzerland: n = 91; Ukraine: n = 963). Across samples, psychological symptoms showed moderate to strong correlations with somatic symptoms (Spearman's r = 0.53–0.69). For all subgroups, three clusters were identified as optimal by the gap statistic. These clusters were differentiated primarily by overall symptom burden, forming low, moderate, and high general distress profiles across psychological and somatic symptom domains. Similar severity-graded patterns were observed in all three samples. Conclusion Across all three samples, psychological and somatic symptoms co-occurred and were differentiated by overall symptom severity. These findings suggest that assessments in young adults should consider symptom burden across multiple domains. Severity-based symptom patterns may also help inform targeted prevention and early-intervention strategies.