Here’s something I found on Wiki:
Citicoline (INN), also known as cytidine diphosphate-choline (CDP-Choline) & cytidine 5’-diphosphocholine is a psychostimulant/nootropic. It is an intermediate in the generation of phosphatidylcholine from choline.
Studies suggest that CDP-choline supplements increase dopamine receptor densities, and suggest that CDP-choline supplementation helps prevent memory impairment resulting from poor environmental conditions. Preliminary research has found that citicoline supplements help improve focus and mental energy and may possibly be useful in the treatment of attention deficit disorder. Citicoline has also been shown to elevate ACTH independently from CRH levels and to amplify the release of other HPA axis hormones such as LH, FSH, GH and TSH in response to hypothalamic releasing factors. These effects on HPA hormone levels may be beneficial for some individuals but may have undesirable effects in those with medical conditions featuring ACTH or cortisol hypersecretion including, but not limited to, PCOS, type II diabetes and major depressive disorder.
Apparently, CDP choline increases GH secretion also, as well as increasing glucose metabolism, blood flow, and dopamine receptor density in the brain! No wonder it’s such an effective mood enhancer!
CDP Choline also helps enhance the signalling of many receptors such as the acetylcholine, norepinephrine, and dopamine.