1065 When the Body Settles, Pain Settles: Anxiety Shapes How Night-Time Movement Predicts Pain Relief

Abstract Introduction Greater objective sleep disturbances amplify subjective pain intensity and unpleasantness through pathways influenced by current and long-term anxiety. Elevated anxiety can diminish therapeutic response to cognitive behavioral interventions for insomnia (CBT-I) and pain (CBT-P), reducing treatment efficacy. This secondary data analysis assesses whether baseline anxiety functions as a moderator of changes in the sleep–pain relationship following CBT-I and CBT-P interventions. Methods Participants were drawn from an NIH-funded RCT (R01AR055160; NCT02001077; McCrae PI) evaluating CBT-I and CBT-P on patients with fibromyalgia and insomnia. The moderation analyses (SPSS) included randomized participants (N = 50; 𝑥- age = 52.87; 96.05% female). Total Sleep Time (TST), Total Wake Time (TWT) were measured using the Actiwatch 2 (Phillips Respironics, Bend, OR), baseline anxiety via the State-Trait Anxiety Inventory (STAI Y1), and daily pain intensity and unpleasantness from 14-day diary averages. Results Significant main effects emerged for changes in TST (TSTch) predicting changes in pain intensity (PIch) (b = .60, p = .004) and pain unpleasantness (PUch) (b = .64, p = .002) from baseline to post-treatment. STAI showed no main effects on either changes in PIch or PUch, but moderated both relationships. For PIch (b = –.01, p = .006), TSTch effects were significant at low (b = .26, p = .004) and average (b = .13, p = .010) levels of STAI. For PUch (b = –.01, p = .002), TSTch effects were significant at low (b = .25, p = .004) and average (b = .11, p = .023) levels of STAI. Models using TWT and those examining change through follow-up were nonsignificant. Conclusion Improvements in objectively assessed TST, but not TWT, immediately following the sleep and pain interventions were associated with lower pain only among individuals with low to moderate anxiety at post-treatment. Improving sleep alone may be insufficient for individuals with elevated anxiety, as anxiety can sustain activation in stress and central pain pathways, driving increased nighttime limb movements and reinforcing central sensitization, a state of increased CNS responsiveness that further intensifies pain. Therefore, addressing anxiety concurrently may be necessary to decrease sleep-impairing limb movements and achieve meaningful pain reductions. Support (if any) NIAMSD