HCRT and Alzheimer disease: Increased CSF orexin levels in MCI due to AD (p < 0.05). CSF orexin was higher in MCI SC (PSQI ≥5, n = 10) compared with MCI wSC (PSQI <5, n = 10, p < 0.001) and compared with both NC (with sleep complaints, PSQI ≥5, n = 11, p < 0.001; without sleep complaints, PSQI <5, n = 15, p < 0.001)