Quick question: Pathfinder / DnD psionics
There is a certain amount of overlap due to limited concept space: you use your powers to read minds and move things. Are you a wizard, casting Mage hand and Detect Thoughts? Are you a psion, using your telepathy and telekinesis? Are you a psychic, invoking spirits to tell you what others think and shake tables?
Conceptually, the two are meant to be somewhat different, possibly best illustrated by the power's 'source' - though it's not a perfect fit in either case.
Psionic power comes from yourself, developing the mental powers you possess and using them on the world and others.
Psychic power comes from the past, learning to contact and manipulate the spirits and imprints of ancient times.
Divine power comes from the gods, channeling their will and making it manifest in the mortal realm.
Arcane power comes from the universe, unraveling its secrets and wielding them to shape your environment.
Another source of conceptual difference is that psionics rely a lot on crystals imbued with power, where psychic magic is more based on emotions than shiny stones.
The abilities you get from either are fairly diverse, and can be fine tuned to get a wide range of builds - some things are easier than others, but you still have a lot of options either way. I'm not aware of any official way to advance both at the moment (though one could probably work one out), so that means they are distinct, I suppose.