Mental Health and Pain pp 119-155
Chronic Pain and the Anxiety Disorders: Epidemiology, Mechanisms and Models of Comorbidity, and Treatment
This chapter provides an overview of the characteristics, theories, and treatments for the comorbidity between the anxiety disorders and chronic pain. Consistent with the majority of research and theory in this area, the primary focus of this chapter will be on comorbid chronic pain and posttraumatic stress disorder (PTSD), a stress- and trauma-related disorder that develops after exposure to a traumatic stressor. In the first section, we provide a definition and description of the features and epidemiology of chronic pain and the anxiety disorders. Data on the comorbidity between the two conditions is then presented, followed by a consideration of the temporal precedence of each condition in the etiology of their co-occurrence. The next section describes the three main theoretical approaches that have been taken to explain the high comorbidity rates; namely, mutual maintenance models, vulnerability models, and a combination of the two. Specific vulnerability factors, such as anxiety sensitivity and sensitivity to pain traumatization, are also discussed. The overlap between the neurocircuitry and neurophysiology common to both chronic pain and PTSD is reviewed, highlighting the role of the amygdala, prefrontal cortex (PFC), insular cortex, and anterior cingulate cortex (ACC). Two major pathways for the development of chronic pain and anxiety disorders are then considered: fear-conditioning and stress-induced analgesia. Finally, current psychological management strategies for both conditions are then considered, with an emphasis on a biopsychosocial approach to treatment. The chapter concludes with a discussion of future research directions.