One of the more interesting questions people who help addicts ask is, why does one substance addict more quickly than another? Is it simply that one substance is stronger than another? Or that one more closely mimics some already present neurotransmitter, some substance we already have in our bodies? Certainly, both these statements seem to be factors. But what affect, then, does the person's state of woundedness have on the speed of this process? Does it even have an effect? Here, too, this also must be a factor.
What about a person's childhood? Does this have an affect on the speed at which someone gets addicted? And the society they live in? What about this? Again, both these things seem to be factors. So what is the answer?
Actually, none of these things is the main factor, although they each do play a role in how quickly people get addicted. What is the main answer then? The answer lies primarily in one thing: the speed at which the substance puts the person into shock.
To see how this works, please take a look at the life event diagram above. First the disclaimer. I have charted four substances and the speed at which they affect a person. Obviously, these are only generalizations. Purer heroin or large quantities of alcohol taken in a short time period can mean they are cause shock more quickly. My point remains, though, and given that I am only averaging their effects, the order I have presented these substances in is a good guideline.
What does the diagram represent?
First recognize the "P" Curves present. Each one represents a plot of the person's experience, from a rapidly rising ability to internally picture to a sudden and shocking fall into a clear lack of ability to internally picture. This curve charts a person's inner experience life.
Next notice the slope of the lines before the point at which the fall. Each substance has a different natural upward slope, each based on the speed of onset. This slope is what makes taking these substances so different and so differently addicting.
Think of the slope as what addicts call "the kick." Literally, this is what the slope does. It "kicks" the person first into an intense state of inner picturing and then suddenly into shock; the severe lack of ability to picture internally.
What does this "kick" have to do with addiction? Literally, it is this sequence of events;  hyperawareness,  sudden kick,  shock; that addicts us to these substances. And similar to the way a more sudden knockout punch would more seriously injure a boxer, the more "kick" a substance has, the more quickly and deeply it addicts the user. Even more to the point, the four ramp inclines directly represent the four different onset times, the times the four substances need to take effect, with crack cocaine being the most rapid, and alcohol being the least. In general, here is why crack addicts more deeply then alcohol, given similar exposures.
So where do all the rest of the factors fit in? For the most part, they are already build into the onset ramps, in that each factor is a part of how quickly each substance takes affect.
Thus, the psychological expectation is a factor, the societal sanctions for or against are factors, the thrill of doing something illegal is a factor, the person's physical makeup is a factor, etc.