The theory of addiction

I'm sure this is a subject that has been explored many many times, but the other night I got into a debate that eventually involved the definition of addiction. Here is the definition according to Webster:

ad·dic·tion
Pronunciation: \ə-ˈdik-shən, a-\
Function: noun
Date: 1599

1: the quality or state of being addicted <addiction to reading>
2: compulsive need for and use of a habit-forming substance (as heroin, nicotine, or alcohol) characterized by tolerance and by well-defined physiological symptoms upon withdrawal; broadly : persistent compulsive use of a substance known by the user to be harmful

And then the definition of addicted:

¹ad·dict
Pronunciation: \ə-ˈdikt\
Function: transitive verb
Etymology: Latin addictus, past participle of addicere to favor, from ad- + dicere to say — more at diction
Date: 1534

1 : to devote or surrender (oneself) to something habitually or obsessively <addicted to gambling>
2 : to cause addiction to a substance in (a person or animal)

The first definition is what I would argue at first thought - that there is a biological basis for addiction. Not only are the physiologic rewards of using the substance, but there is tolerance of the substance (i.e. as someone uses the substance over time, it takes larger amounts of the substance to get the same high) and if you take it away, there are symptoms of withdrawal. Now the first thing this made me think was that substances that many people think are not addictive, probably are actually addictive by this definition. For example, drugs like marijuana, acid, and mushrooms are not thought of as biologically addictive, however, I think if you use these substances often enough, there are definitely symptoms of withdrawal, although they might not be as severe as some other substances. So are these substances than addictive? I think so - which is a change from how I used to think.

This leads into my second thought - that the "addictiveness" (how fast you can get addicted to a substance, or how long it takes) and symptoms of withdrawal are very different depending on the drug. Some drugs people can take once (e.g. cocaine, meth) and get immediately addicted whereas others it seems that you can use for a while before getting physiologically addicted (e.g. tobacco). Of course, this depends on the user as well, as there are genetic and environmental issues that are involved. Likewise, some withdrawal symptoms are mild, but some can even cause death, so clearly, the drugs are different. Does this translate into different levels of addiction? As an immediate answer, I think so... Clearly, if you can get addicted faster to a substance - that should mean it's more addictive. If your withdrawal symptoms are worse for a particular substance, probably you would do more desperate things to get the drug. For example, in the news you hear of crack addicts or heroin addicts robbing people, even the occasional murder to get the drug or get money to buy the drug. You don't hear that much for things like marijuana or mushrooms. Acid I have no idea. I guess I don't pay that much attention. I think this is very interesting because clearly some addictive things are legal - e.g. tobacco and alcohol. Legalizing some substances, like crack, cocaine, heroine, meth, seems like it would be impossible, and probably ethically wrong, because they are relatively easy to get addicted to and the withdrawal symptoms are horrible, not to mention the health issues of taking those drugs in the first place. However, if something is not that addictive, and symptoms of withdrawal are not that bad, does that mean that it's okay to be legal? Clearly the government thinks alcohol and tobacco are of a low enough addictiveness to be legal.

Finally, the last thing this made me think was that perhaps this definition was a bit restrictive. People have been known to engage in other behaviors that are harmful to themselves and are termed addiction - for example, an addiction to gambling or shopping. Although there are no withdrawal symptoms, people have a compulsion to do these things which are potentially (and usually) harmful to themselves. Myself - I have a potato chip addiction (especially ones with fake cheese). You could argue that maybe there is a biological basis for these people's behavior - maybe gambling gives them a natural rush, maybe a low-level state of excitement that they crave while gambling somewhat similar in nature to the adrenaline rush that adventure-seekers or sports-players seek. But that's a little murkier and far-fetched. I'm not saying impossible, but it's definitely in the realm of the unknown at this point.

I think this is a very interesting topic and deserves a lot more thought than I have time to give. Maybe when I'm retired.