Many addictions are overwhelming ( often but not always chemically) driven habitual obsessions. Whatever the addiction maybe. Without getting to the root cause of why and some people are more susceptible to become addicts than others. Adequate support is also another very important factor in helping a person to overcome their addiction. Any small chink in the amour will cause failure. Sadly, we seem to have more addictive opportunities than ever before with not just substance abuse (and there are umpteen new substances being used too) but internet access there are the gamboling addictions for example. These may not kill directly but they ruin lives and relationships in the same way.