ABSTRACT
OBJECTIVE: Fibromyalgia (FM) is a chronic pain condition associated with depression. However, self-efficacy (belief in own ability to manage symptoms) and social support may be protective. This study tested three types of social support (emotional, tangible, and instrumental) for moderation of the mediating effect of self-efficacy on the relationship between FM impact and depression over time. METHODS: Six hundred participants with FM were randomly assigned to no intervention, social support group, or combined self-management and social support. The Fibromyalgia Impact Questionnaire, Norbeck Social Support Questionnaire, FM-modified Arthritis Self-Efficacy Scale, and Center for Epidemiological Studies-Depression surveys were administered at baseline, 6, 12, and 18 months. There were no significant intervention effects on the variables of interest, however, participants' scores were used to assess four longitudinal models. RESULTS: Self-efficacy showed mediation both between (b = 0.104, p < .001, 95% CI = [0.071, 0.137]) and within (b = 0.89, p < .001, 95% CI = [0.073, 0.106]) individuals. Only tangible support demonstrated moderation of the relationship between FM impact and self-efficacy, and only between individuals (b = 0.154, p = .022, 95% CI = [0.022, 0.287]). CONCLUSION: The results indicated that self-efficacy attenuated a portion of the effect of FM impact on depression over time. Additionally, higher levels of tangible support (the belief that your social network can provide you with assistance) were related to weaker influence of FM impact on self-efficacy over time. These factors may be important targets for the prevention of depression in people with FM.
