I'm doing an internship topamax 100 mg for weight loss Actor Cory Monteith, known for his starring role as Finn on "Glee," has checked into rehabilitation, People magazine reports. Monteith, 30, has "voluntarily admitted himself to a treatment facility for substance addiction," his rep told the magazine, adding that the actor asks for "respect and privacy as he takes the necessary steps towards recovery." It isn't the first time. Monteith has been open about his struggles with substance abuse in the past and previously admitted he checked into rehab for the same issue at age 19.