Negative affect, self-report of depressive symptoms, and clinical depression: Relation to the experience of chronic pain

Objective: The goal of this study was to examine the relative importance of global affective distress, self-report of depressive symptoms, and presenc e or absence of major depression to the experience of chronic pain. Setting: A multidisciplinary pain program at a university medical center wa s the setting for this study. Patients: Subjects in this study were 211 consecutive patients with chronic pain. Outcome Measures: Pain duration, compensation, and litigation status were c ontrolled for in the statistical analyses, as each correlated significantly with at least one of the measures of affect. Global affective distress was assessed using the Global Severity Index (GSI) from the Brief Symptom Inve ntory. The Beck Depression Inventory and the Center for Epidemiological Stu dies Depression Scale were used as measures of self-report of depressive sy mptoms. Presence or absence of major depression was based on DSM-IV criteri a. Results and Conclusions: The GSI, Beck Depression Inventory, and Center for Epidemiological Studies Depression Scale were significantly correlated wit h each measure of the experience of pain, although clinical depression was only significantly related to self-reported disability and negative thought s about pain. The self-report measures of depression maintained their relat ion to the dependent measures when the somatic items from the scales were r emoved, suggesting that the relations were not spuriously due to the influe nce of pain symptoms on the scales. When examining the unique contribution of each variable to the experience of pain (by simultaneously controlling f or the other measures of affect), the GSI was uniquely related to the senso ry and affective components of pain. Self-report of depressive symptoms was more highly related to a measure of the evaluative component of pain and u niquely related to self-reported disability and negative thoughts about pai n. The results are discussed within the context of theoretical models of th e relation between pain and affect, and suggestions for future research ate presented.