Los Angeles, April 8 : Singer Robbie Williams believes that drug abuse allows real demons to enter your life and has stated that his addiction to prescription pills was his most damaging vice. Speaking on the 'Bought the T-Shirt podcast, Williams said: "I think drugs are like the equivalent to a Ouija board and you don't know what you're opening up. I think when people talk about demons and sorting out their demons, I think they are actually demons." The former 'Take That' star says of all his vices, his addiction to painkillers was the worst and caused him the most harm, reports 'Variety'. He shared: "Let me tell you, the worst time I've ever had with drugs are painkillers. "Nothing is a day trip or a walk in the park but pain medication is f****** evil. Meanwhile, the people that own the parent for those pain medications are currently loving in 50,000 sq ft houses." Williams only started taking drugs to try and cope with the enormous fame he experienced as a member of 'Take That'. The 'Better Man' hitmaker, who was in the boy band with Gary Barlow, Jason Orange, Howard Donald and Mark Owen, was thrust into the limelight when he was just 18 following release of their hit single 'It Only Takes A Minute' in 1992, and as a natural "introvert", he started drinking alcohol and using substances to try and live up to the reputation other people bestowed upon him. He said: "I took drugs to fill in the blanks. When fame came to me at a very early age, I was 16, when I joined 'Take That', it magnified all of the negative aspects of who I thought I was. Before that I was quite content but I was vulnerable and incredibly sensitive. I felt like I'd been born with an open wound." "Then when I was thrown into this mosh pit of show business it magnified the negative aspects of my own self-doubt." "I took drugs to become the person that the world was telling me I should be. When really I'm an introvert, and it's OK to be an introvert. I'm an introvert with extrovert tendencies. I'm an extrovert for a living but I'm an introvert in real life." /IANS