Detection of malingering: psychometric evaluation of the Chinese version of the structured interview of reported symptoms-2.

BACKGROUND

Malingering detection has emerged as an important issue in clinical and forensic settings. The Structured Interview of Reported Symptoms-2 (SIRS-2) was designed to assess the feigned symptoms in both clinical and non-clinical subjects. The aim of the study was to examine the reliability and validity of the Chinese version of this scale.

METHODS

Two studies were conducted to evaluate the reliability and validity of the Chinese Version of SIRS-2. In Study one, with a simulation design, the subjects included a. 40 students asked to simulate symptoms of mental illness; b. 40 general psychiatric inpatients and c. 40 students asked to reply to questions honestly. Scales scores for feigning symptoms among three groups were carried out for discriminant validity of the Chinese Version of SIRS-2. Minnesota Multiphasic Personality Inventory-2(MMPI-2) was administered in 80 undergraduate students. In Study two, with a known-groups comparison design, scales scores for feigning symptoms were compared between 20 suspected malingerers and 80 psychiatric outpatients from two forensic centers using the Chinese Version of SIRS-2.

RESULTS

The Chinese Version of SIRS-2 demonstrated satisfactory internal consistency in both study one and two. In study one, criterion validity of this scale was supported by its significantly positive correlation with the MMPI-2 (r = 0.282 ~ 0.481 for Infrequency), and by its significantly negative correlation with the MMPI-2 (r = -0.255 ~ -0.519 for Lie and -0.205 ~ 0.391 for Correction). Scores of 10 out of 13 subscales of the Chinese Version of SIRS-2 for simulators were significantly higher than scores of honest students and general psychiatric patients. In study two, the mean scores of the Chinese Version of 13 subscales for suspected malingerers were significantly higher than those of psychiatric outpatients. For discriminant validity, it yielded a large effect size (d = 1.80) for the comparison of the participant groups in study one and two. Moreover, the sensitivity (proportion of malingerers accurately identified by the measure) and specificity (proportion of people accurately classified as responding honestly) of the Chinese version of SIRS-2 in the detection of malingering in these two studies are acceptable.

CONCLUSIONS

The Chinese version of the SIRS-2 has good psychometric properties and is a valid and reliable tool for detection of malingering in Chinese populations.