Mindflight. Mindsaga, #1

The government of Earth has one main secret weapon in its cold war against its former colony worlds--telepathic spies. But what even the spies don't know is that once they reach their late thirties, they begin to develop strange symptoms that leave them mentally and physically unstable. The Terran Intelligence Agency routinely terminates these unstable telepaths to keep them from threatening the stability of the project as a whole.
Alain Cheney is one of the best telepathic agents in the TIA's arsenal. For 14 years he's been loyal and dependable. But now that he's showing symptoms of the instability, the Agency decides to eliminate him--and just when a secret development occurs that could change the future of the inhabited galaxy. To survive, Alain must find safety somewhere. But he can't trust his enemies, and certainly not his friends....