Somatization symptoms in chronic low back pain patients.

Chronic low back pain (CLBP) patients often are described as "somatizers", who report multiple somatic complaints beyond back pain itself, but the nature and clinical significance of this observation is poorly understood. To clarify the characteristics, correlates and severity of somatization in CLBP, we rigorously assessed somatization symptoms in a sample of patients not selected for psychiatric or pain clinic referral. Male CLBP patients (N = 97), attending a primary care orthopaedic clinic, and matched healthy controls (N = 49), were assessed using the Diagnostic Interview Schedule III-A (DIS), Beck Depression Inventory (BDI), Hamilton Rating Scale for Depression (HRSD), McGill Pain Questionnaire (MPQ), Sickness Impact Profile (SIP), and the Pain and Impairment Relationship Scale (PAIRS). Although none of the subjects met strict DSM-III criteria for a lifetime diagnosis of Somatization Disorder, 25.8% of CLBP patients reported a lifetime history of 12 or more somatic symptoms, as compared to only 4.1% of controls. In the less symptomatic ranges, patients still generally reported more symptoms than controls, with 51.5% of patients vs. 8.2% of controls reporting 7-11 symptoms, and 22.7% vs. 87.8% of controls reporting 0-6 symptoms (p < .001). Major depression and alcohol dependence were significantly associated with increased severity of somatization (p < .05). Lower mood and increased impairment, but not pain intensity, were related to greater number of somatic complaints. Symptoms of somatization are prevalent, but not universal, in CLBP and the pattern of these symptoms is reminiscent of the "spectrum of severity" reported in other medical populations. Recognizing this spectrum of somatization may lead to better patient-treatment matching and improved clinical outcomes.