A biopsychosocial perspective examining the conjoint influence of multiple factors has been the dominant paradigm for studying depression in RA among behavioral medicine researchers.10 Much of this research has focused on the contributions of disease activity, pain, and disability to mood disturbance. Many studies have shown that heightened disease activity, pain, and disability may lead to depression.11 However, in addition to the independent effects of these variables, cyclical, synergistic relationships among these factors may partly explain their impact on depression. One scenario posits disability may be the final common pathway through which these other factors affect depression. For example, high disease activity may give rise to pain that creates impairments in functioning, including disability. Disability, in turn, may contribute to depression by interfering with mobility, performance in social roles, or by limiting the ability to engage in meaningful or valued life activities. Once mood deteriorates, patients may struggle to cope with their pain and self-manage their condition, further perpetuating this downward spiral.
Another way to view the impact of disease-related factors is to consider them as risk factors, not as actual determinants of depression in RA. The rationale for this perspective is that psychological factors also have been shown to affect depression and may either mitigate or exacerbate the effects on disease characteristics. For example, illness beliefs may affect the interpretation of symptoms and disease course and reflect the underlying meaning to patients of being sick or incapacitated by their medical circumstances. For instance, considerable research over the past 25 years has shown that the perception of helplessness in the face of pain or heightened disease activity plays a central role in depression in RA.12 Likewise, catastrophizing—the tendency to have dire thoughts about pain or the consequences of RA—may contribute to both depression and anxiety.13
Dysfunctional beliefs about RA may also lead to maladaptive coping that, in turn, contributes to depression. For example, helplessness has been associated with passive or avoidant pain coping strategies that negatively impact mood.14 In contrast, internality (perception of control) is related to active pain coping that tends to be protective of mood. Illness beliefs and coping mechanisms may serve as important explanatory links between disease activity and mood, functioning as mechanisms through which factors such as pain and/or disability lead to depression and emotional distress (see Figure 1). The implication of this model is that treating disease activity is insufficient for the amelioration of depression. Emphasizing the implementation of strategies to correct dysfunctional beliefs or improve pain coping mechanisms may lead to improvement in mood.
