Showing The Strange Power by L. J. Smith

The strange power: Kaitlyn is an artist, but not an ordinary one; everything she draws comes true. When she is invited by Dr Xetes, a scientist who is studying psychic abilities, to join his school of "talented individuals" in California, Kaitlyn is only too happy to go. There she meets Rob, a healer, and Gabriel, a dark lone wolf, who apparently wants nothing to do with her. But with so much supernatural energy going around, it's hardly surprising that the psychics soon develop a telepathic link that can't be broken.
The Possessed: Having learned the dark secrets of the psychic institute, Kaitlyn and her new friends are on the run, not even daring to contact their parents or old friends. As the group hide-out together they grow closer and Kaitlyn finally discovers Gabriel's dark secret: he's a psychic vampire. In order to survive he needs to drain other people's life-force, but he's been holding back to keep others safe. Kaitlyn offers herself as a source - and finds the experience not entirely un-enjoyable.
The Passion: Back at the lab, captured like animals, Kaitlyn and her friends are still in danger from the evil Dr Xetes. To escape they will need to face the true meaning of what their psychic link really means. But Kaitlyn is battling with an internal conflict too: Rob or Gabriel? Sunlight or darkness? She'll need to search her heart for the answer.