In the present study, we investigated the differences in cerebrospinal fluid (CSF) orexin-A levels among patients with different neurocognitive disorders, such as mild or moderate to severe Alzheimer’s disease (AD; mAD, msAD, respectively), behavioral variants of frontotemporal dementia (bv-FTD), non-fluent primary aphasia (NFPA), and idiopathic normal pressure hydrocephalus (iNPH). This evidence concerns the gene HCRT and frontotemporal dementia.