The study measured several brain chemicals in spinal fluid from older people with Alzheimer's or vascular dementia and compared them to healthy seniors. It found that most of the chemicals were lower in the diseased groups, while the sleep‑related peptide DSIP was a bit higher in Alzheimer's patients but unchanged in vascular dementia. The changes didn’t link to how long someone had been sick.

Cerebrospinal fluid (CSF) levels of several neuropeptides have been suggested as candidate markers in neurodegenerative disorders. We have examined the levels of corticotropin-releasing hormone (CRH), beta-endorphine (BEND), delta sleep-inducing peptide (DSIP), somatostatin (SRIF), and neuropeptide Y (NPY) in CSF samples obtained under highly standardized conditions from healthy aged controls and from patients suffering from Alzheimer's disease (AD) or vascular dementia (VAD). The influence of some potentially confounding factors was evaluated. CRH and BEND were markedly decreased in both AD and VAD patients, and BEND levels correlated negatively with degree of dementia within the patient population. SRIF was decreased in both AD and VAD patients. DSIP was slightly increased in AD, but not in VAD. NPY did not differ between groups. For none of the peptides did CSF concentrations correlate significantly with duration of illness, nor, with the exception of BEND, with its degree. Present data do not support the hypothesis that specific neuropeptide changes occur in different neurodegenerative disorders, but are in agreement with previous reports suggesting that neuropeptide systems are differentially affected by neurodegeneration.