Laboratory findings include ≥2 sleep-onset REM episodes and objective sleep latency ≤8 min on the multiple sleep latency test.119 The presence of cataplexy and undetectable levels of hypocretin in the cerebrospinal fluid (<110 pg/mL) distinguishes narcolepsy type 1 from narcolepsy type 2.120 The cause of narcolepsy is multifactorial and includes genetic and environmental determinants. Here, HCRT is linked to narcolepsy without cataplexy.