Chronic Pain Patients and the Nonorganic Physical Sign of Nondermatomal Sensory Abnormalities (NDSA)

The nonorganic physical sign of nondermatomal sensory abnormalities (NDSA) is frequently found in chronic pain patients. The presence of NDSA qualifies the patient for a potential DSM-III diagnosis of conversion disorder. DSM-III (Axis I and II) diagnoses and personality styles were assigned to 283 mixed chronic pain patients. Discriminant analysis was used to identify diagnoses and personality styles significantly related to NDSA. The demographic variables of workers' compensation (WC) status, age, sex, and race were used as control variables. The discriminant function comprised all control variables, and psychiatric diagnoses accounted for only 22.1% of the variance. Age and WC status, i.e., the demographic variables, explained most of the variance (16.8%), with psychiatric diagnoses adding little (5.3%). The vast majority of the variance is unexplained, indicating the presence of ''unexplained'' factors for the presence of NDSA in chronic pain patients.