Here are some signs of heroin addiction that make it hard for me to believe Angelina Jolie is a junkie:
injection wounds, track marks, needle marks - numerous photos of her wearing sleeveless dresses and open-toed shoes
infections on the skin from injections, boils - see above
small, constricted pupils - looked at recent pics of her and her pupils appear normal
appearance of “distant” gazing eyes (some say heroin steals the soul) - nope
lack of motivation - in addition to having 5 kids and being a well-traveled humanitarian, she's spent the past several years directing, acting, and screenwriting
placing distance from friends and family members or hanging out with a new group of people - she's not close to her father...wonder if she's still close to her brother though (her father took him to this year's Golden Globes)
communication flaws, difficulty speaking, slurring speech - very eloquent
lack of memory, forgetting things or not remembering important events or matters - have never heard horror stories about her ability to remember lines/show up on time/behave on set
lack of interest in the future or what comes next - her double mastectomy shows she thinks about the future
unkempt self-image, lack of hygiene or taking care of one’s self - she always looks pretty put-together in candid shots...although the not eating thing is kind of strange
Overall, I think it's plausible that Angelina was a heroin addict in the past, but there's been nothing to show she's been using in the past ten years or so.