4. METHODS OF PAIN ASSESSMENT
Pain is a wholly subjective experience; thus, objective assessment is hindered. Traditionally, pain has been evaluated using three main approaches: patient self-report, behavioral observations, and physiologic indicators. In addition, there is growing evidence for the use of psychophysical, neurophysiological, and neuroimaging techniques to objectively complement those assessments (Table 1). However, accurately applying these modalities in patients with OUD requires nuanced understanding of their respective strengths and limitations, particularly considering the biopsychosocial and opioid-related variables of interest.
Notably, the pain assessment tools utilized in various observational and randomized controlled trials evaluating both acute and chronic forms of pain in individuals with OUD are often inconsistent, as there is limited evidence to justify the choice of one tool over another, reflecting the need to develop consensus on optimal evaluation methods for this complex population. Additionally, although the psychometric properties of the assessment self-report scales have been widely reported97-99, providing evidence of reliability and validity, psychometric evaluation is often absent for populations of persons with both pain and OUD.