Zac Efron has reportedly been to rehab twice this year for cocaine addiction, according to TMZ.

Sources told the website Efron was doing the drug for more than two years, and had used Molly, a type of Ecstasy. He left California in March and entered an outpatient program.

He returned to Los Angeles in May and begin filming Seth Rogen's film "Neighbors." He apparently relapsed during shooting, which, reports say became obvious on the set because he wasn't showing up for work.

He went through a second program after filming and has apparently been clean since.

Sources told TMZ four things are driving his drug use. He has issues with his parents, who are still trying to control his life.

Well OK -- everyone's parents do that. If that was a reason to do drugs, lots of people would ... oh.

Also, sources told TMZ Efron's upset about his movie career, which hasn't gone as well as he wanted.

So he gets upset, does drugs, doesn't show up for work, and hurts his career even more. Irony can be so ironic.

He has "girl issues." Well OK -- every guy does. If that was a reason to do drugs, lots of people would ... oh.

He's been hanging around "a bad group of friends" who introduced him to cocaine. It's always that "bad group of friends," isn't it? TMZ reports, though, that the bad people are no longer in Efron's life.