The research team assembled a mixed sample of 955 participants drawn from Iran, combining 143 psychiatric patients who met DSM-5 criteria for somatic symptom and related disorders (SSRD) with 812 individuals from the general population who did not carry that diagnosis. The sample had an average age of 34.2 years, with a standard deviation of 11.5 years, and was 66 percent female. This design deliberately blended a clinically severe group with community participants, allowing the investigators to examine how somatization relates to other forms of psychopathology across a wide spectrum of severity rather than only within a narrow patient population.

Methodologically, the study took what the authors describe as a multidimensional approach. Participants completed a battery of self-report questionnaires covering somatic symptoms, psychological syndromes such as depression and anxiety, and two distinct ways of characterizing personality pathology. The first, criterion-based approach reflects the traditional categorical diagnosis of personality disorder, in which individuals are judged against diagnostic checklists. The second, trait-based approach follows the newer dimensional model, assessing maladaptive personality traits as continuous dimensions. By including both frameworks, the researchers could test whether the answer to their question depended on how personality pathology is defined — a critical check, because the field of personality assessment is currently in transition between these two paradigms.

To reduce the many questionnaire items to interpretable constructs, the team used exploratory factor analysis, a statistical technique that identifies clusters of variables that covary together and can be treated as underlying latent dimensions. This procedure extracted four factors corresponding to somatization, psychological syndromes, criterion-based personality disorder, and maladaptive trait-based personality pathology. In other words, the data themselves organized into the conceptual categories the researchers set out to compare, providing a clean foundation for the predictive analyses that followed.

The heart of the study lay in hierarchical linear regression, a technique that allows researchers to enter predictors in stages and measure how much additional variance each block explains. Here the logic was straightforward but powerful: if somatization were fundamentally a manifestation of personality pathology, then personality measures should explain substantial variance in somatic symptom reporting even after current psychological distress is statistically controlled. Conversely, if somatization is chiefly tied to present distress, the psychological syndromes factor should dominate. The results were unambiguous, and the effect sizes were striking.

Compared with criterion-based personality disorder, the psychological syndromes factor was far more strongly related to the somatization factor. The psychological syndromes accounted for an R-squared of 0.512, meaning they explained just over half of the variance in somatization scores, whereas criterion-based personality pathology explained only 0.105. In the hierarchical models, the incremental contribution — the change in R-squared — was 0.414 for psychological syndromes against a mere 0.007 for criterion-based personality disorder. The same pattern emerged when the trait-based model was used instead: psychological syndromes achieved an R-squared of 0.512 versus 0.138 for maladaptive traits, with incremental values of 0.377 versus 0.004. Whichever lens was applied to personality, the conclusion held.

The team also examined a single-item, pain-related measure as a separate outcome, and here too psychological syndromes outperformed both personality frameworks, though with smaller absolute effects. The syndromes factor explained an R-squared of 0.151 for the pain measure, compared with 0.067 for criterion-based personality disorder and 0.066 for trait-based pathology. The incremental contributions were 0.086 for psychological syndromes against 0.003 and 0.001 for the two personality approaches respectively. The authors are careful to note that these pain findings rest on a single-item indicator and should not be generalized to multidimensional assessments or to chronic pain conditions, where the underlying dynamics may differ considerably.

What do these numbers mean conceptually? The authors conclude that somatization appears to be a phenomenon primarily related to psychological distress rather than to personality pathology, and that this holds regardless of the theoretical context used to define personality problems. This does not mean personality pathology is irrelevant. The study found that both criterion-based and trait-based personality pathology were independently related to somatization, so the association is real. But when current psychological distress is taken into account, personality pathology shrinks to a marginal predictor. In practical terms, a patient’s present levels of depression, anxiety, and related syndromes carry most of the predictive signal for bodily symptom reporting, while personality structure adds only a thin residual layer of explanation.

The clinical implications are significant. Somatization is notoriously difficult to treat, and patients with somatic symptom and related disorders often consume substantial health care resources through repeated investigations and specialist referrals that yield little relief. If the strongest statistical lever for understanding somatization is current psychological distress rather than entrenched personality pathology, then interventions targeting distress — such as treatments for depression and anxiety — may offer the most direct route to reducing the burden of somatic symptoms. The authors explicitly frame their findings as a way to refine theoretical models and improve clinical outcomes by targeting the most impactful constructs, and the variance figures suggest that distress-focused constructs are precisely those impactful targets.

The study also carries methodological lessons for the research community. Because the pattern of results was consistent across both categorical and dimensional conceptualizations of personality pathology, the conclusion is not an artifact of one diagnostic school. The use of factor analysis to establish latent dimensions before regression, and the hierarchical entry of predictors to isolate incremental validity, provide a template for similar comparative questions in psychopathology research. The work was approved by the ethics committee of the Mind GPS Institute of Kermanshah, Iran, conducted in accordance with the Helsinki Declaration, and supported methodologically by that institute without external funding. As with any cross-sectional, self-report study, causal direction cannot be established, and the general-population sample from a single country invites replication elsewhere. Yet the sheer size of the gap — psychological syndromes explaining roughly half the variance in somatization while personality pathology explains a tenth or less — makes this one of the clearer statistical verdicts the field has received on a long-standing debate, and it points clinicians firmly toward treating the distress, not just the personality, when the body speaks for the mind.

Subject of Research: The relative contribution of psychological syndromes and personality pathology to somatization

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

Article References: Komasi, S., Macina, C., Miettunen, J., Nazari, A., Heydarpour, B., Shams-Alizadeh, N., & Amianto, F. (2026). Relative sensitivity of phenotypic personality pathology and psychological syndromes to somatization phenomenon: a multidimensional approach. Discover Mental Health. https://doi.org/10.1007/s44192-026-00615-0

Image Credits: AI Generated

DOI: 10.1007/s44192-026-00615-0

Keywords: somatization, somatic symptom and related disorders, personality pathology, psychological distress, DSM-5, hierarchical regression, factor analysis, maladaptive traits, pain, psychopathology, mental health, Relative