To develop an illness perception scale of somatization symptom and complete the reliability and validity test, so as to provide a new tool for illness perception evaluation of somatization symptom in patients with non-psychotic mental disorders.

Form May 2020 to January 2022, 473 non-psychotic patients with somatization symptom were selected from the outpatient and inpatient department of the Sichuan Provincial People′s Hospital and Sichuan Psychiatric Medicine Center. According to the literature research method, semi-structured interview method, the existing illness perception scale and the clinical experience of psychiatrists, the total item pool of the scale was obtained (n=46), consequently, the item pool was modified by a discussion of the research group and Delphi expert consultation method was used to form a predictive scale. Two hundred and three patients were invited to complete the measuring scale, and the items of the predictive scale were screened according to the results of item analysis to form a formal scale. Exploratory factor analysis was used to construct the scale dimension. The formal scale was tested in 270 patients, Cronbach α coefficient was used to evaluate the reliability of the total scale and each dimension, and Pearson correlation analysis was used to verify the retest reliability. AMOS equation model verifies the structural validity of the scale, and Pearson correlation analysis is used to verify the criterion validity of the scale with PHQ-15, GAD-7 and PHQ-9 as criteria.

A total of 443 patients′ valid information was collected. According to the results of discussion by the research group and letters from experts, the prediction scale with 36 items was finally obtained, and 20 items were removed according to the results of item analysis. There were 16 items in the formal scale, including four dimensions: disease distress, symptom understanding, treatment attitude and medication attitude, which could explain the variation rate of 57.702%. The correlation coefficient between the total score of the scale and PHQ-15, GAD-7 and PHQ-9 was 0.395-0.506. Confirmatory factor analysis indicates that the model is ideal (χ²/df=1.719, GFI=0.922, CFI=0.937, NFI=0.865, IFI=0.939, RMSEA=0.055) and has good validity. The internal consistency coefficient and test-retest reliability correlation coefficient of the total scale and the four dimensions are 0.683-0.831 and 0.746-0.836, respectively, and the reliability results are satisfactory.

The scale has good reliability and validity, and can be used to measure the disease cognition of patients with non-psychotic mental disorders on somatization symptoms.

Somatization symptom; Illness perception; Reliability test; Validity test