Relative sensitivity of phenotypic personality pathology and psychological syndromes to somatization phenomenon: a multidimensional approach

Insight into the distinctiveness of different psychopathological profiles associated with somatization helps refine theoretical models and improve clinical outcomes by targeting the most impactful constructs. The present study aimed to evaluate the predictive validity of somatization by both criterion-based and maladaptive trait-based personality pathology after controlling psychological syndromes. We used data from a mixed sample including 143 psychiatric patients with somatic symptoms and related disorders (SSRD) according to the DSM-5 criteria and 812 non-SSRD from the general population of Iran ( n = 955, 34.2 ± 11.5 old years, 66% female). Data collected by several self-report questionnaires were analyzed by exploratory factor analysis and hierarchical linear regression. Four factors for somatization, psychological syndromes, criterion-based personality disorder (PD), and maladaptive trait-based PD factors were extracted. Compared to the criterion-based PD, the psychological syndromes factor was more related to both the somatization factor ( R 2 = 0.512 versus 0.105; ∆ R 2 = 0.414 versus 0.007) and the single-item, pain-related measure ( R 2 = 0.151 versus 0.067; ∆ R 2 = 0.086 versus 0.003). Compared to the maladaptive trait-based PD, the psychological syndromes factor was also more related to both the somatization factor ( R 2 = 0.512 versus 0.138; ∆ R 2 = 0.377 versus 0.004) and the pain-related measure ( R 2 = 0.151 versus 0.066; ∆ R 2 = 0.086 versus 0.001). It seems that somatization is a phenomenon primarily related to psychological distress rather than personality pathology, regardless of theoretical context. Although personality pathology is independently related to somatization, it appears to be a marginal predictor when current psychological distress is taken into account. Findings regarding pain should be interpreted specifically in relation to the single-item, pain-related indicator used in this study and should not be generalized to multidimensional or chronic pain conditions.