"Zac Efron completed a rehab program in 2013 without the media being any wiser about his problems, but the actor's now speaking out about his difficulties with drugs and alcohol. ""It's a never-ending struggle,"" the 26-year-old told <a href=""http://www.hollywoodreporter.com/news/zac-efron-career-reinvention-addiction-699529"" target=""_blank"">The Hollywood Reporter</a> in its May 9 issue."