1365 Navigating Marijuana Withdrawal: A Diagnostic Dilemma in MSLT Interpretation

Abstract Introduction Limited prior studies and case reports have assessed the effects of marijuana use and withdrawal on sleep architecture, including alterations in REM sleep. In particular, these have suggested an increase in REM and reduction in REM latency with abrupt discontinuation of chronic marijuana use. This case report examines a patient with suspected narcolepsy type 1 and highlights how recent marijuana cessation may significantly influence Multiple Sleep Latency Test (MSLT) results, potentially leading to diagnostic misinterpretation. Report of case(s) A 29-year-old female presented with non-restorative sleep, poor sleep quality, excessive daytime sleepiness requiring multiple daily naps, involuntary dozing, sleep paralysis, hypnagogic hallucinations, and possible cataplexy-like episodes. She disclosed daily marijuana use at the initial consultation visit. Home sleep apnea testing was non-diagnostic for obstructive sleep apnea. Subsequently, the patient completed a two-week sleep diary, followed by in-laboratory polysomnography (PSG) and MSLT. Her sleep diary documented an average of 9 hours and 3 minutes of sleep per night, including daily napping. Overnight PSG demonstrated mild obstructive sleep apnea (AHI 8.2; CMS AHI 3.6) with adequate total sleep time of 6 hours and 44 minutes and no sleep-onset REM period was present. Testing proceeded to the MLST, which was significantly abnormal, with rapid sleep onset on all naps leading to a mean sleep onset of 0.6 minutes. Notably, 5 sleep-onset REM periods were observed. The patient denied the use of medications that could influence test results. A urine drug screen performed between naps 3 and 4 was positive for marijuana, with a Delta-9 carboxy-tetrahydrocannabinol concentration of 10 ng/mL. The patient reported last using marijuana two days before the in-lab sleep studies. Conclusion The patient’s MSLT findings may be confounded by the physiologic effects of marijuana withdrawal, particularly the potential for REM rebound. Although the clinical picture and objective results raise strong suspicion for narcolepsy type 1, the MSLT cannot be considered valid under these conditions. Repeat evaluation—including actigraphy and a sleep diary for two weeks, followed by repeat PSG and MSLT—is necessary. Critically, the patient must abstain from marijuana use for at least six weeks before repeat testing to ensure accurate assessment. Support (if any)