Conceptualizing and examining the role of stress in arthritis: a comment on Harris et al.

It has long been known that having arthritis is associated with significant psychiatric comorbidity [1]. For example, approximately 20 to 30 % of patients with arthritis suffer from depressive disorders [2]. It has also been confirmed that having arthritis is a stressful experience for many patients, and that stress may contribute to greater pain, disease activity, and mood disturbance in diagnosed patients [3]. However, while research has documented the negative psychological impact of having arthritis on patients in community samples over time [4], it has never been substantiated that psychological factors, including stress, increase the risk of developing arthritis. This vitally important knowledge would broaden our understanding of the etiology of arthritis and its management. Furthermore, based on evidence that stress may contribute to disease onset, novel treatment strategies could be developed and implemented that could prevent the onset of arthritis, potentially reducing its worldwide prevalence and impact. While longitudinal studies that are executed on the population level are difficult to design and execute, they provide unique opportunities for examining prospective relationships that can alter our perspective of an entire field. The study by Harris et al. [5] is noteworthy for its magnitude and the significance of its findings. The authors reported results suggesting that perceived stress may have an independent role in the development of arthritis. Using data from a sample of over 12,000 participants from the Australian Longitudinal Study of Women’s Health assessed at 3-year intervals, the authors found that perceived stress significantly increased the odds of having arthritis over time. Their multivariate modeling approach, which included a time lag, confirmed the effect of stress on the onset of arthritis 3 years later, while controlling for the contribution of other psychological factors, behavioral variables, disease comorbidities, and health care use. Interestingly, social support, a potentially mitigating factor as a stress buffer, did not protect patients from the onset of arthritis. Nevertheless, greater social support is associated with better mental health functioning in patients who have been diagnosed with arthritis and face the challenges of coping with their illness [6]. Their data also demonstrated that stressful life events were not predictive of arthritis onset. The results illustrate the importance of distinguishing between objective stressors from the feeling of being stressed, showing that the latter is more prognostic of the onset of arthritis. While the objective and subjective components of the stress process have been long debated and studied in the behavioral medicine literature [7], this finding may have particular relevance to autoimmune disease. Subjective stress is correlated with depression and anxiety that drive the sympathetic, neuroendocrine, and immune systems that, in turn, can exacerbate the inflammatory response. Hypothetically, chronic stress might increase the propensity for developing arthritis in persons with genetic vulnerability for autoimmune disorders. Whether this is true or not warrants empirical scrutiny. On a more practical note, it is important to identify patients who are stressed in clinical practice who may be at risk for arthritic conditions. Clinicians can easily assess perceived stress in medical settings by querying patients about their perceived burdens and/or by administering brief self-report instruments [8]. In addition, the Harris et al. study raises important questions about the distinction between osteoarthritis (OA) and rheumatoid arthritis (RA), and whether their data are applicable to either or both conditions. Although their survey P. M. Nicassio (*) Department of Psychiatry, School of Medicine, University of California, Los Angeles, CA, USA e-mail: pnicassio@mednet.ucla.edu