The Effects of Medical or Psychiatric Diseases on the Association between Morningness-Eveningness and Somatization

Abstract

Objective: Morningness-eveningness (M-E) has been found to be associated with various psychiatric disorders or symptoms. However, the relationship between ME and somatization has not yet been fully investigated. This study aims to explore the relationship between ME and somatization. Methods: A total of 171 subjects (mean age: 41.1±8.2 years; 42.7% males) were recruited from the Incheon area, Republic of Korea. All subjects were asked to complete questionnaires including the Horne and Ostberg morningness-eveningness questionnaire (MEQ), the Center for Epidemiological Studies Depression Scale (CES-D), and the Symptom Checklist Somatic from the Symptom Checklist-90-Revised (SCL-SOM). Multiple regression analysis was used to test hypotheses. Results: The MEQ and CES-D scores were predictors for the SCL-SOM score (MEQ: β=−0.185, p=0.001; CES-D: β=0.234, p<0.001). In subjects without medical diseases, both the MEQ and CES-D were predictors for the SCL-SOM score (MEQ: β=−0.179, p=0.007; CES-D: β=0.220, p<0.001). However, only the CES-D score, and not the MEQ score, was a predictor in subjects with medical diseases (CES-D: β=0.230, p=0.019). Similarly, the CES-D score was the only significant predictor in subjects with psychiatric diseases (CES-D: β=0.277, p<0.001); both the MEQ and CES-D scores were significant predictors in subjects without psychiatric diseases (MEQ: β=−0.243, p<0.001; CES-D: β=0.203, p=0.002). Conclusion: ME and somatization are significantly associated, independent of depression or anxiety status, indicating that somatization is independently influenced by morning-evening preference. An association between ME and somatization is evident only in subjects without medical or psychiatric problems.