Somatization and Sleep Pathology from a Transdiagnostic Dimensional Perspective: Insights into Detachment Spectrum from a Large Community

Objective: Somatization and sleep problems are psychiatric conditions with high comorbidity that appear to be more influenced by emotional dysfunctions than by other transdiagnostic constructs.The present study aimed to predict dimensional measures of somatization, poor sleep quality, insomnia severity, nightmare severity, and nightmare frequency using the transdiagnostic construct of detachment manifestations.Materials and Methods: An online survey was conducted to collect crosssectional data from 1,106 Iranian adults (64% female; mean age =329.6 years; age range =17 to 73 years) between August and December 2023.Participants completed the measurement inventory of detachment manifestations, the revised form of the symptom checklist-90, and several validated questionnaires assessing sleep disturbances.Data were analyzed using Pearson correlations and multiple linear regression analyses.Results: Only the self-focused pattern of detachment manifestations significantly predicted somatization (R 2 =0.23, p<0.001), poor sleep quality (R 2 =0.15, p<0.001), insomnia severity (R 2 =0.20, p<0.001), nightmare frequency (R 2 =0.10, p<0.001), and nightmare severity (R 2 =0.14, p<0.001).Specifically, both subtypes of the self-focused pattern-dissociative (=0.16 to 0.45, all p0.002) and self-body manifestations (=0.08 to 0.18, all p<0.05) were meaningful predictors of nearly all criterion variables. Conclusion:The self-focused pattern of detachment manifestations -especially the dissociative subtype-is a key construct in predicting somatization and sleep problems.A better understanding of the phenomenology and underlying mechanisms underlying somatization and sleep disturbances within transdiagnostic frameworks requires shifting the focus from emotional dysfunction to the detachment spectrum.