I believe that is because smack is alot harder to come by without money, where as a ciggarette is easy to borrow 20 times a day if you ask enough people.
I had been a serious addict of cannabis for over ten years in my past, to the point of near physical self destruction. Not any more, I gave up once, for 6 months, started again then quit fully and am now clean for life. I also have experiences with alcoholism and other addiction in my family. So while I don't claim to be an expert I certainly am talking from the personal side of the coin and not the judgemental outside viewpoint.
There are three types of addicts in my extended philosophies on the subject.
There are those who tell themself they are addicted but then convince themself they will quit tomorrow every day and then fail for another day. Always pushing the limits of their mental and physical endurance because they know that one day they plan to give up and lose the dependancy. This is a dangerous game because often this type of addict will push too far and one of two things will happen. One, they get so sick that they scare themself into instant cold turkey. Two, they get so sick that they sadly cannot handle it and they close their eyes and give up. This type of addict is usualy too smart to be an addict but too addictive in personality to give up before things become really desperate. It doesn't really matter what toxin they become addicted to because it is mostly a habit or routine addiction, a lifestyle for them, it defines who they are and often they don't see it as a negative characteristic untill it's almost too late.
There are the addicts who cannot stand their life so much that they intoxicate into early death. Psychological trauma or long term physical pain can be the kind of catalysts that set the downward spiral in motion. They are also often the kind of addicts who know they have a problem but they do not even pretend to want to reform. They are on the downward slope and will find it much harder to get off without forced abtinence or exceptional will power.
There are thirdly the addicts who refuse to belive they are addics. They are surprisingly the least affected physicaly because they refuse to accept the damage they are doing to their body. The placebo makes a huge difference. They are addicted in a totaly physcial sense, usualy to the more addictive substances; worst of all alcohol or prescription/over the counter drugs. The reason these are the worst is because socialy they carry the least negative energy. Everybody drinks, right? Everyone takes sleeping pills sometimes, right? This type of addict is the most healthy but potentialy the most dangerous to themself and others due to the pure ignorance of what they are poisoning themself with daily.
There are obviously other types of addicts, adrenalin for one obvious example, excersise for another. But I believe in basic format we can break down substance addicts into one or more of those three catagories the majority of the time. Amy Winehouse was the second type. she was very unhappy and she commited suicide without really accepting that she was doing it.
