Introduction and Objective: Understanding the psychological mechanisms underlying somatic symptoms can clarify the processes involved in psychosomatic problems and facilitate the design of targeted therapeutic interventions. The present study aimed to examine the structural model of the effect of insecure attachment on somatic symptoms, with mentalization and difficulty in emotion regulation serving as mediating variables in adults.

Research Methodology: The research design was correlational and employed structural equation modeling (SEM). The statistical population included all individuals aged 18 or older living in Hamedan who had consulted a physician in 2024 with somatic symptoms. A sample of 295 individuals was selected using convenience sampling. Data were collected using several standardized assessment tools, including Fraley et al.’s Attachment Scale (2011), the Difficulties in Emotion Regulation Scale by Gratz & Roemer (2004), the Reflective Functioning Questionnaire by Fonagy and Luyten (2016), and the Somatic Symptom Disorder-B Criteria Scale by Toussaint et al. (2016).

Results: The results indicated that insecure attachment to close friends, mothers, fathers, and partners had a significant negative impact on mentalization (β = -0.12 to -0.39, p < 0.05) and a significant positive impact on somatic symptoms (β = 0.15 to 0.27, p < 0.01). The analysis revealed a significant indirect relationship between insecure attachment and somatic symptoms, mediated by mentalization and emotion regulation, across all models (p < 0.05). The fit indices for the four models, including RMSEA ≤ 0.066 and CFI > 0.96, indicated good fit.

Conclusion: Therefore, insecure attachment can lead to somatic symptoms by reducing mentalization capacity and increasing difficulties in emotion regulation. These results underscore the importance of addressing mentalization processes and emotion regulation skills in psychotherapeutic interventions for psychosomatic disorders.