Acute Versus Chronic Pain

Central to the modern conceptualization of persistent clinical pain is the distinction between acute and chronic pain. Acute pain is caused by incomplete healing of tissue. It is primarily nociceptive. The first priority in treatment is to address the injury or disease causing nociception. Rest generally promotes healing and pain relief. It is increasingly recognized that adequate treatment of acute pain not only increases patient comfort but also speeds healing and functional recovery. Even brief periods of intense acute pain can induce neuronal remodeling and central sensitization of pain pathways. Guidelines for the appropriate management of acute pain have been published by the Agency for Health Care Policy and Research (Acute Pain Management Guideline Panel 1995). The panel recommended that both nonpharmacological interventions - including cognitive and behaviorally based interventions (e.g., relaxation, imagery, biofeedback, education) - and pharmacological interventions be used to manage postoperative and other acute pain. Because many of the nonpsychiatrically trained clinicians involved in the management of acute pain may lack the training and experience to provide these therapies, it is important that psychiatrists recognize this contribution they may be able to make to improving patient care.

Chronic pain is pain that persists beyond the completion of tissue healing. This time can vary according to the tissue damaged, but 6 months is a convenient marker for most types of clinical pain. Chronic pain is often not nociceptive. Treatment is generally directed to the pain and associated disability rather than the original disease or injury. Because psychiatrists are rarely involved in the management of acute pain, the remainder of this chapter focuses on the treatment of chronic pain.