Strategy for understanding how expectations interfere with chronic pain management: a multi-modal neuroimaging study.

Chronic pain is a societal problem that affects more than a quarter of Canadians. The suffering caused by debilitating pain is detrimental to proper functioning in day to day life. It is unclear why people with this condition suffer pain when there are no detectable signs of tissue injury. Pain medications that are generally effective for acute pain are ineffective for about half of chronic pain sufferers for unclear reasons. Failed pain treatments lead to need for higher doses of potentially addictive or risky pain medications. There are currently no tests for pre-identifying patients who are at risk of treatment failure. To improve the treatment selection process, we first need to understand why pain treatments are ineffective for so many people with chronic pains. Our previous studies have demonstrated that response to treatments may be linked with expectations. Negative expectations can reduce the effectiveness of a treatment or can even amplify pain in some but not all people with chronic pain. The brain systems through which the brain learns associations and uses cues to build expectations may be organized differently in people at risk of treatment failure. Most research on this topic has relied on experimentally evoked pain or on measuring responses to placebos (sham treatment). This study proposes to integrate mechanistic evidence garnered from an experimental study with clinical attributes of patients who suffer with chronic pain. These findings can be expected to lead to new evidence-based pain therapies and will contribute to new assessment tools for pre-screening people who are more likely to experience treatment failure. Clinicians should be able to select treatments that fit the patient's specific mental and biological makeup. In this way, we aim to help to make the treatment process more streamlined, cost effective and are determined to improve the lives of people with chronic pain.