HCRT and hypocretin deficiency: In the ICSD3, narcolepsy caused by hypocretin deficiency is called “type 1 narcolepsy” while other hypersomnias (not likely due to hypocretin abnormalities) will stay subdivided into “type 2 narcolepsy” in the presence of a positive Multiple Sleep Latency Test (MSLT) with multiple Sleep Onset REM periods (SOREMPs) vs idiopathic hypersomnia otherwise (for more detail see American Psychiatric Association [1]).