Amanda Bynes' drug use led her to hate her own appearance.

The 32-year-old actress has spent the last few years away from the spotlight after her drug abuse caused her career to spiral downwards, and Amanda - who claims to have been sober for the last four years - has now revealed how her use of Adderall undermined her ability to perform on the set of the 2011 movie 'Hall Pass'.

Amanda - who was replaced by Alexandra Daddario shortly after filming began - confessed: ''When I was doing 'Hall Pass', I remember being in the trailer and I used to chew the Adderall tablets because I thought they made me [more] high [that way].

''I remember chewing on a bunch of them and literally being scatterbrained and not being able to focus on my lines or memorise them for that matter.''

Amanda - who first experimented with drugs during her teenage years - can still vividly remember the drugs causing her to hate her own on-screen appearance.

Despite this, the actress has rubbished suggestions she was fired from the movie.

She told PAPER magazine: ''I remember seeing my image on the screen and literally tripping out and thinking my arm looked so fat because it was in the foreground or whatever and I remember rushing off set and thinking, 'Oh my god, I look so bad.'

''I made a bunch of mistakes but I wasn't fired. I did leave ... it was definitely completely unprofessional of me to walk off and leave them stranded when they'd spent so much money on a set and crew and camera equipment and everything.''

Amanda - who suffered a very public breakdown before entering rehab - remembers having a similar feeling while watching 'Easy A', her last film project before her acting hiatus.

She admitted: ''I literally couldn't stand my appearance in that movie and I didn't like my performance. I was absolutely convinced I needed to stop acting after seeing it.

''I was high on marijuana when I saw that but for some reason it really started to affect me. I don't know if it was a drug-induced psychosis or what, but it affected my brain in a different way than it affects other people. It absolutely changed my perception of things.''