Depressed pain patients differ from other depressed groups: Examination of cognitive content in a sentence completion task

Depression is a common feature of chronic pain, but there is limited research into the content and frequency of depressed cognitions in pain patients. A limitation of previous research is the failure to include nonpain depressed comparison groups. The present study used a sentence completion task to investigate the content of cognition in 4 groups of participants: with pain and concurrent depression, pain without depression, depression without pain, and with neither pain nor depression. One hundred seventy-two participants generated sentences to a set of predefined stems. Complete responses were coded by affective valence (negative, positive, and neutral) and health-related content. As predicted, participants with depression (with and without pain) produced more negative responses than nondepressed participants (with and without pain); participants with pain (depressed and nondepressed) produced more health responses than those without pain (depressed and controls); participants with depression and pain produced more negative health responses than any other group. The strengths of the current study are the inclusion of the depressed nonpain group, the use of a comprehensive coding scheme applied by 2 independent raters, and the presence of depression validated through a diagnostic interview. In contrast to depressed groups without pain, participants with pain and depression exhibit a cognitive bias specific to negative aspect of health. This focus facilitates understanding of the relationship between depression and pain processing: The implications for therapeutic interventions are discussed. (C) 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.