Reelin

Crystallographic structure of the reelin protein based on the PDB: 2DDU​ coordinates. Boghog

Reelin is a complicated chemical found floating around in your body. Near as I can tell, it has some influence over the central nervous system. I got onto this from a Reddit link to a Wikipedia passage about schizophrenia, one of my least favorite diseases.

I'm not very good at chemistry. Oh, I understand the basics well enough, water is made of two hydrogen atoms and one oxygen atom, but once you get past the basics there is an endless profusion of chemical compounds and I quickly become lost. It's almost like the English language, you can stick words, or atoms, together in a limitless number of ways. If you use it every day, those combinations will become familiar to you, like the books you have read. But if you don't immerse yourself in this sea of arcane knowledge it will always be gibberish.