Mike Williams talks to scientists and former addicts to try and discover why pleasure and desire leads to dependency in some people but not in others.
Mike Williams investigates the biochemistry of the brain's reward system in an effort to detect the cause of addiction. How can things which initially bring such pleasure become such a destructive force? something that's start off being pleasurable end up making us feel so low? Mike Williams talks to scientists and former addicts who speak frankly as he searches for some answers.
Presenter: Mike Williams
First broadcast on the BBC World Service.