Chris Carter at UK Premiere of 'The X-Files: I Want to Believe' held at the Empire Leicester Square - Arrivals. London, England - 30.07.08

Just a week after X-Files star David Duchovny checked into rehab to seek sex addiction counselling, Carter has been diagnosed with an acute sleeping disorder and admitted to hospital.

A source tells EW.com Carter's problems stem from "working on multiple films back to back over a two year period".

Source: WENN