Is House always high?

So, House is addicted to Vicodin because his leg hurts and it helps him with the pain. In one episode from S1, Cuddy challenges House to stop taking vicodin for one week in exchange for one month without clinic duty, and Cuddy says something along the lines of "You don't really need the pills, you just like getting high!" so it got me wondering... is House always high then? or does the vicodin only makes the pain go away without any other mental effects?