I think this depends on how long the person has been using and how often. I am a believer in the fact that chemical changes happen in your brain when you chronically use a substance so some kind of intervention is need and I think it is very difficult to just go "cold turkey".
Yes, a person can but I agree with TomInKan that it depends on many factors.
But the problem in addiction isn't stopping cocaine. It's stopping cocaine and learning how to stay away from cocaine and other drugs. So while it's not necessary to go to a treatment facility to beat coke in the short term, it's a good idea to go to one to beat coke in the long term.
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