I looked it up in the dictionary pyschics and the second entry was medium so psychics and mediums are the same thing.
Yes I believe that their are people who are sensitive to things. My great whatever grandfather was dying in was in the late 1800's. Anyway he didn't trust any of his family except a sister to tell her where he buried his money. She was sick and didn't get there till after he died. They went to woman in area who saw things. She told them where it was by describing it was like north of house, so many far etc. Anyway they didn't find it. Much later a family member was walking around their property and found a strong box. On investigating they found the ruins of a house and a whole right where she said to dig. None of them remember the original house. But some one in the county did cause the story had spread about where she said to dig.
As for mediums or psychics. YES. Had personally had an experience that leaves me in no doubt of them.
However there are many who lay claim to each of these different abilities that are just blowing smoke and con the public.