I believe there is cause for belief in psychic phenomena, but I come from a different direction - that of the quantum mechanics and consciousness. I just don't see how elevated levels of serotonin increase whatever it is that the brain does to "feel" future events. In other words, I don't see the mechanics in the psychics.
Just find someone who can read the cycles and they will appear to have psychic abilities...Obviously, there are some who are more skilled than others at understanding this stuff, but the best ones routinely call turns ahead of time.
Psychic phenomena...maybe, to a slight degree. But I believe the best of traders...simply have the experience in their given market of instrument. -- that makes it appear like they have a magic touch. KISS: keep it simple stupid. Be a Master of One -- not a jack of all trades.
Advance pattern recognition and a willingness to think outside the box. See what is, instead of what you want and act on it. Possibly the ability to slot away in your subconscious large amounts of seemingly unrelated information and let it sort out the answers you are looking for. Some people are naturals at it, others can train themselves, and others dismiss it. Sort of like the Envoys in Richard K. Morgans book Altered Carbon.
I don't think it is just serotonin either. Just bringing it up since it was quoted in the video you linked. But psychics do drink certain teas which relaxes the mind -- perhaps opening up the sub-conscious?