APPLICANT?S DESCRIPTION: This grant focuses on individual differences in the stress response as significant factors determining who develops a chronic pain syndrome characterized by widespread pain, and who is unable to recover from it. Maladaptive responses to pain and withdrawal from positive social interactions are studied as key factors that underlie the affective distress and persistence of fibromyalgia symptoms. To test this model three well established methods of inquiry are used: 1. Field assessments of responses to stress, developed in prior research on arthritis patients, and 2. Laboratory tests of stress reactivity under controlled experimental conditions. 3. Longitudinal follow-up of patient status 2 years after pre-tests. Two groups of Osteoarthritis participants are studied: (1) 150 OA participants who meet criteria for Fibromyalgia (FM), and (2) 200 participants with osteoarthritis (OA) who report levels of pain comparable to the FM group, but who do not display the classic tender point symptoms found among those with FM. Longitudinal assessments on all subjects as well as thorough initial testing will permit three types of comparisons. 1.The examination of case-control differences between groups of FM respondents and those with OA only. 2.The examination of variables predictive of recovery among those with FM. 3. The examination of those factors predictive of the onset of widespread pain among the OA sample that displayed only regional pain at the initial assessment.