Catastrophizing, Pain, and Pain Interference in Individuals With Disabilities

Chronic pain is a significant problem for many individuals with disabilities, such as spinal cord injury (SCI) and multiple sclerosis (MS).1–4 Moreover, recent research indicates that a number of psychosocial factors that have been shown to contribute to the experience of pain, distress, and disability in individuals who present with chronic pain as a primary problem are also associated with measures of patient functioning in individuals with disabilities and chronic pain.5–10 Pain catastrophizing, in particular, has been consistently shown to predict patient functioning across most, if not all, populations of individuals with chronic pain.10–12 Pain catastrophizing refers to a propensity to focus on and magnify pain sensations, and to negatively evaluate one’s ability to cope with pain.12 Research has shown that individuals with chronic pain who catastrophize report higher levels of pain intensity, psychological distress, and disability, and also report higher rates of healthcare usage, longer hospitalizations, and greater use of pain medication than those who do not catastrophize.12 Longitudinal research has also shown that catastrophizing can lead to greater pain intensity, functional impairment, and depression.11 These findings have generally been replicated in samples of individuals with physical disabilities and chronic pain. For example, castrophizing has been shown to be positively associated with measures of distress and disability in individuals with SCI,10,13 and with pain intensity and disability in individuals with phantom limb pain.14 Catastrophizing has also been shown to be significantly associated with greater pain intensity, increased pain interference, and poorer psychological functioning in patients with MS.15 Research in individuals who present with pain as a primary problem (e.g., chronic low back pain) suggests that women tend to catastrophize more than men.16 Moreover, when catastrophizing cognitions are controlled, statistically significant sex differences in pain intensity and distress that are often observed (women reporting higher levels of both17,18) disappear.11,19 These findings suggest that catastrophizing may play an important role in the differences that are sometimes observed between men and women in pain and distress. However, because previous studies have focused on individuals with primary chronic pain problems, it is not clear whether such sex differences extend to individuals with chronic pain that is secondary to a disability. Sex may also moderate the relationship between catastrophizing and measures of pain and dysfunction, although this possibility has only been examined in very few studies. In one such study, Hirsh and colleagues20 found a stronger association between pain, mood and disability in women compared to men in individuals with low back, myofascial, neck, arthritis, and fibromyalgia pain. While this paper did not directly examine catastrophizing, it did suggest the possibility that men and women may differ in how psychosocial variables are related to pain and other important pain-related variables; such differences could potentially extend to catastrophizing. In other words, among women, the association between pain and disability may be mediated by negative mood and psychological functioning, while psychosocial factors may play less of a role in these associations for men.20 Along these lines, Sullivan and colleagues19 reported that women differ from men in their behavioral responses to pain. These investigators cited several studies demonstrating that women (a) report more health care utilization than men, (b) take more sick days than men in response to pain, and (c) are more likely to go on short-term disability following a pain-related condition compared to men. Despite these previous findings suggesting differences between men and women in the associations among pain-related variables (including psychosocial variables), no study has yet examined the relationship between sex, catastrophizing, pain, and dysfunction in individuals with a disability and chronic pain. Knowledge concerning these relationships is important because, if sex differences are found, this raises the possibility that men and women may benefit from different treatment interventions or approaches. Determining the extent to which such sex differences are found in individuals with a disability and chronic pain is also important because the rates of many disabling conditions vary between men and women. For example, and of most relevance to the current study, approximately 80% of spinal cord injuries occur in men,21 whereas MS is twice as common in women.22 The analyses performed in this study were designed to help advance our understanding of the role that sex may play in the associations among psychosocial factors and physical functioning, and how certain psychological variables, such as catastrophizing, may be associated with pain and dysfunction in two distinct disabilities (MS and SCI). Specifically, the purposes of this study were to: (1) determine if the sex differences in catastrophizing that have previously been found in other pain groups replicate in a sample of patients with chronic pain that is secondary to a disability (MS or SCI); (2) examine, for the first time, the possible moderating effects of sex on the associations between catastrophizing and measures of pain and functioning in individuals with MS and SCI; and (3) explore possible differences in catastrophizing between MS and SCI groups, and whether the associations between catastrophizing and measures of pain and functioning vary as a function of disability group. Based on the results of previous, relevant research, we hypothesized that women will report greater catastrophizing than men across both disability groups studied. We also anticipated that the association between catastrophizing and critical outcome variables will be stronger for women than for men. Given the lack of previous research examining differences in psychosocial variables between disability groups, we did not have specific hypotheses concerning possible similarities and differences in the associations between catastrophizing and measures of pain and functioning between patients with MS and SCI; therefore, the analyses for the third study purpose were considered exploratory.