As an addiction, it bears many similarities to others. But there are many differences, too. Here’s a big one.
THERE IS NO REAL PLEASURE FROM SMOKING. In contrast to other addictions, this has no bearing on the brain’s pleasure center. But the pleasure that smokers report must be explained. here it is.
Once dependent (it takes about 4 cigarettes to be hooked – as per the research of the tobacco companies), one begins experiencing withdrawal symptoms when the body craves the next cigarette. The range for this to occur is about 18-23 minutes after the last one. Most people manage to delay the next cigarette for a while, but it eventually becomes easier to undergo whatever bother there is to smoke than to tolerate the discomfort. Well, the removal of the discomfort is experienced as if it were pleasure. So it is pleasure by association.
The addiction to smoking is primarily a physical dependence on nicotine. Yes, there are “oral” habits, and these can be satisfied by chewing on a pencil, toothpick, gum, etc. But on the whole, this is the least significant part of the smoking habit/addiction.
For those who smoke, be aware that the issurim involved in terms of incurring health risks are as serious as chilul Shabbos. The poskim have spoken about this. No sooner than one would brazenly be mechalel Shabbos, or eat chazzer, should one light up a cigarette. This is straight from the poskim. I have commented in other threads on the subject with detailed lists of the poskim. I find it hypocritical for someone to be machmir on anything and still smoke.
Since we are during Sukkos, it is necessary to add an additional note. The heter that is used to smoke on Yomtov is that it is similar to eating, and is considered דבר השוה לכל נפש. In America, it does not qualify, as smoking is still a rather small percentage of the population (considering the majority needed to qualify). In Eretz Yisroel, the poskim are still debating the issue, which has become more relevant as fewer people are smoking.