Because it goes much deeper than physical dependence. Like smoking it acts as a screen against painful emotions and experiences. As a qualified and experienced counsellor and hypnotherapist I have to do a lot of work with people with these behaviours to deal with the underlying causes to enable any change to be permanent rather than just change substances or behaviours.
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Ian - Pagan Editor
"We can never obtain peace in the outer world until we make peace with ourselves."
"With realization of one's own potential and self-confidence in one's ability, one can build a better world. "
Dalai Lama