0986 Inter-Individual Differences in Sleep Architecture of Patients Receiving Methadone for Opioid Use Disorder

Abstract Introduction Methadone treatment for opioid use disorder (OUD) reduces drug cravings and promotes abstinence, but sleep disturbances can negatively impact OUD recovery outcomes. Irregular sleep architecture and respiratory disturbance in outpatients administered methadone as medication for OUD (MOUD) are common, but inter-individual differences may be substantial. We investigated the magnitude and stability of inter-individual differences in sleep architecture and respiratory measures in outpatients in their first 90 days of MOUD treatment. Methods N=6 adults (42.5±10.4y, four females) enrolled in local MOUD programs participated in this research study. The daily methadone dose varied between participants (75.8±23.2mg, range 50-120mg). All participants reported past use of multiple substances; four reported current mental health disorders; and four reported chronic pain. As part of the study, participants underwent two consecutive nights of cardiorespiratory PSG, with lights off at 21:49 on average (range 21:17-22:16) on both nights. Sleep stages and apnea-hypopnea index (AHI) were analyzed for systematic inter-individual differences using variance components analysis. The stability of inter-individual differences was quantified with the intraclass correlation coefficient (ICC, ranging from 0 to 1 for negligible to complete stability). Results On night one, mean±SD was 441.9±21.1min for total sleep time (TST), 9.0±5.2min for sleep latency (SL), 35.3±22.4min for wakefulness after sleep onset (WASO), 28.8±26.6min for N1, 220.8±58.6min for N2, 114.0±77.2min for N3, and 78.3±65.6min for REM. AHI scores were 16.4±9.1, indicating moderate sleep apnea on average. Compared to similarly aged healthy adults, N1 was low, and TST, WASO, N2, REM, and AHI were high. Stability was significant and substantial for N1, N2, REM, and AHI (ICC≥0.68, F≥5.19, P< 0.05). Conclusion Despite small sample size, we found substantial, stable inter-individual differences in N1, N2, REM, and AHI, whereas TST, SL, WASO, and N3 did not reach statistical significance. Varying methadone doses, prior substance use, physical and mental health, chronic pain, and (epi)genetic predisposition may partially account for these inter-individual differences. Our PSG data were collected in-laboratory, not naturalistically; results should be interpreted accordingly. Given the substantial, stable inter-individual differences in sleep architecture, a personalized approach to sleep management may be crucial to help improve OUD recovery outcomes. Support (if any) WSU ORAP and HSCL