Examination of the Modified Somatic Perception Questionnaire (MSPQ) in a large sample of credible and noncredible patients referred for neuropsychological testing.

OBJECTIVE: The current study evaluated MSPQ sensitivity to noncredible PVT performance in the context of external incentive, and examined MSPQ false positive rates in noncompensation-seeking neuropsychology patients; and investigated effects of ethnicity/culture, gender, and somatoform diagnosis on MSPQ scores, and relationships with PVT and MMPI-2-RF data.

METHOD: MSPQ scores were compared in credible (n = 110) and noncredible (n = 153) neuropsychology referrals.

RESULTS: Noncredible patients scored higher than credible patients. When the credible group was divided into those with somatoform orientation (n = 39) versus those without (n = 71), the credible nonsomatoform group scored lower than the other two groups, who did not differ from each other. MSPQ elevations were found in ethnic minorities, and in individuals who learned English as a second language or concurrently with another language. MSPQ elevations were also associated with chronic systemic diseases, neurologic illness, and substance abuse. Women scored higher than men, but men and women were equally represented among those patients scoring beyond cut-offs. MSPQ scores were minimally related to PVT data but were more strongly correlated with MMPI-2-RF scales, particularly over-report validity scales, RC1, and Somatic/Cognitive scales, with more widespread relationships observed in noncredible patients.

CONCLUSIONS: A cut-off of 18 resulted in few false positives in credible nonsomatoform patients, and appears appropriate for identifying physical symptom over-report (due to malingering or somatoform orientations), with associated sensitivity of 29%. However, clinicians are cautioned regarding using the MSPQ in patients with systemic, neurologic, and substance abuse conditions, and in ethnic minorities and non-monolingual English-speakers.