Noncredible Complaints and Symptom Validity in Patients With Chronic Pain.

Introduction: The multifactorial nature of pain complicates assessment of the validity of presenting symptoms and behaviours in people with chronic pain. Recently, the Personal Problems Questionnaire (PPQ) was developed to assess genuine and noncredible cognitive, emotional and physical complaints. Here, the PPQ was used to investigate the extent to which patients with chronic pain report noncredible complaints and the relationship with pain severity and measures of cognitive performance validity and symptom over-reporting. Materials and Methods: Seventy-five participants with chronic pain recruited from outpatient and pain management programme clinics completed the clinical and validity scales of the PPQ, the short-form McGill Pain Questionnaire (SF-MPQ) subscales and the Medical Symptom Validity Test (MSVT), and a subsample (n = 27) completed the Personality Assessment Inventory (PAI). Results: Significant mean (T-score±SD) elevations were observed across the PPQ cognitive (64.5 ± 13.1), emotional (65.1 ± 13.2) and physical (77.4 ± 11.0) clinical domains. Endorsement of implausible complaints on the PPQ was common; 35.6% of patients endorsed noncredible pain/physical complaints, while 19.2% and 33.3%, respectively, reported implausible cognitive and emotional difficulties. Multivariate analyses indicated that the odds of likely noncredible responding significantly increased in cognitive (34%) and emotional domains (26%) and in the physical domain (12%) for every point increase on the SF-MPQ affective and sensory pain subscales, respectively. Noncredible symptom reporting was elevated in those receiving disability benefits/involved in litigation (n = 27), but not significantly after controlling for pain severity. Negative impression management on the PAI was associated with implausible cognitive and emotional symptom endorsement, but there was a limited relationship between PPQ validity scales and MSVT underperformance. Conclusion: The PPQ is a potentially useful tool in the assessment of chronic pain patients, with implausible symptom endorsement found in a significant proportion, although this may not reflect intentional exaggeration.