This is a question that will always be out there, as everyone has their own thoughts about it.
A psychic connects with your energy but doesnt know who is telling them this or they recognise that it's their guides working with them.
A medium connects to spirits energy and gives evidence of them, they recognise who they are connecting to.
A medium can work mediumistically and psychically but a psychic can't work upwards.
Hence the saying "All mediums are psychic but not all psychics are mediums"