Psychological and social correlates of the back pain classification scale.

The Back Pain Classification Scale (BPCS) identifies patients whose low back pain reflects a primary psychological disturbance. BPCS scores were related to the MMPI, State-Trait Anxiety Inventory, Multiple Affect Adjective Check List, and Social Readjustment Rating Scale scores; to distribution, intensity, and activities affecting pain; and to social characteristics of 116 patients. High scores on the BPCS (psychological disturbance) are associated with elevated MMPI profiles, and with more widely distributed and more intense pain. Stepwise multiple regression solutions indicate that the MMPI Hypochondriasis (Hs) scale accounts for 15.5% of the variance. No other variable accounts for as much as 3% of the variance. Scores on Hs relate primarily to words in the BPCS psychologically disturbed pole, supplying convergent validity to the BPCS. BPCS scores are unrelated to social characteristics, implying usefulness with the variety of patients seen for evaluation of low back pain.