AbstractOrexins are hypothalamic neuropeptides that regulate several physiological functions, such as appetite, arousal, cognition, stress, sleep and metabolism. Emerging pieces of evidence suggest an orexinergic dysfunction in several neuropsychiatric disorders, including depression, anxiety and addiction. A syndromic overlap between behavioural variant frontotemporal dementia (bvFTD) and several psychiatric disorders was recently demonstrated. Therefore, we analysed cerebrospinal fluid (CSF) orexin A concentrations of 40 bvFTD and 32 non-demented patients, correlating neuropeptide concentrations with several clinical characteristics. A significant increase of orexin A concentrations was found in bvFTD patients when compared to controls (p<0.001). CSF orexin A concentration showed a correlation with Mini-Mental State Examination scores, drug assumption, history of compulsive behaviour and extrapyramidal signs. Moreover, we found a relationship between CSF markers of neurodegeneration, total tau and Aβ_1–42 and CSF orexin A concentrations. Our study provides evidence of an orexinergic dysfunction in bvFTD, correlating with several clinical symptoms. Further larger studies are needed to confirm our data.