"If novelty is addictive, then why do people get addicted to stuff like nicotine which is THE SAME THING DAY AFTER DAY?" - A dear friend of mine after reading an early draft of "Behavioral Addiction"Because you aren't addicted to novelty, you are addicted to dopamine, and novelty is one surefire way to get your brain to release it. There are, however, alternative methods through which to forcibly trigger your reward pathways.
It's drugs. I'm talking about drugs.
Today's topic is chemical addiction: A physical dependance on the introduction of a foreign substance into the body. Although "addiction" may refer to a situation in which an individual simply uses a substance to excess, in the context of this post, we're referring to situations in which users build up a tolerance to their drug(s) of choice, become physically dependent on its presence to function, and experience withdrawal symptoms if they attempt to quit.
How Drugs Affect the Brain and Body
The "How Drugs Work" series covers how individual drugs work (and you can always request new topics) but all drugs act in the following manner:
Drug is consumed → Immediate gratification → Drug is broken down and normalcy is restored if no permanent changes have been made to the brain or body
Here, "immediate" means there is an obvious connection between the consumption of a drug and the effects. You don't eat a mushroom and have it kick in the next day, for example. Addiction and physiological dependance arise when the body and brain adapt to the presence of the drug in the body, and change around it in such as way as to require more of the drug to produce the same psychotropic effects, and eventually making the drug's presence necessary for the user just to feel "normal" and function as they had before they ever took it in the first place. Here's how it happens.
Drug tolerance is composed of two factors: Physiological resistance (body size, genetic resistance) and consumption. The first you're born with, and the second arises as a direct result of your drug consumption.
Let's use alcohol as our example drug (See: "How Alcohol Works" for more detail). If you are descended from an alcohol-loving population, you may be genetically resistant to the effects of alcohol as these individuals naturally produce more alcohol dehydrogenase than those without a history of alcohol use. This means that you are more efficient at breaking down alcohol and flushing it from your system, thus, you can consume more alcohol than those whose bodies don't give them the same advantage from the get-go.
Humans, however, can also build up their tolerance to drugs through use. The more you take (over time) the better the body becomes at metabolizing that particular chemical. As time goes on, the original amount (drinks to get drunk, dosage to get high...) has less and less of an effect.
Eventually, you get to the point where that amount of your drug of choice will do nothing at all. So you up the amount you consume, but by then, your body is already changing itself, altering your body's chemistry to operate under the assumption that the drug in question is present at all times, and that's when dependance starts.
Dependance and Withdrawl
Drug dependance arises as a result of your body's attempts to compensate for the presence of what is essentially poison being continually put into your system. I say "poison" because unlike the things are bodies are built to deal with on a regular basis, drugs are treated like a threat. Food, for a contrast, is broken down into its component parts, which are stored or used to build new things. Drugs are broken down and flushed from our system as fast as our bodies as do the job. Unfortunately, these same cleaning materials can be pretty harmful, too.
Heroin, as you can see below, is one of the most addicting drugs we know of. You can become addicted to heroin quite quickly because your body's reaction (the high, and then the subsequent attempt to save your butt from heaving a heart attack) is so extreme. Heroin is a depressant, so your brain and body start pumping out more things to keep you awake and alive. Take the heroin away, and you've got a ton of stuff floating about that you just don't need.
Let's compare two different drugs, shall we? Alcohol, and Marijuana. You'll notice, by the way, that marijuana isn't even on that chart down there. Why? Keep reading.
Chart via wiki commons, developed by Nutt et al. (2007)
Alcohol: Alcohol's presence prevents the release of dopamine and the transmission of GABA. To counteract this, your body goes into a hyper-excited state in an attempt to bring you up to normal functionality. It forces the creation and release of more GABA and dopamine, and increases neuron sensitivity. Remove the alcohol from that equation, and you're so hyped up you can't function. You're a jerk when drunk, and psychotic when "sober". You can end up having seizures; sometimes just from waking up after a night's sleep, during which all alcohol in your system has evaporated. I've seen it happen. It ain't pretty. There's also this thing called "Kindling"(PDF) where if you develop a cycle of binging and abstaining, you wind up with brain damage, so even if you say "Hey, I only drink [a lot] once a week!" you're still messing up your frontal cortex.
And this is just alcohol; in that chart up there, it's considered moderate.
Marijuana: THC only works with the dopamine your body makes on its own. It does not force the creation of more dopamine than you already have, nor does it introduce anything that mimics any other chemical. Once you're out of dopamine to enjoy, you're out, and you have to wait for your brain make more.
To clarify: Marijuana doesn't force your body into a reactionary state, nor would your body have anything to react to. THC causes no physical damage, and decays on its own. This means you cannot, physically, get addicted to weed in the same way as you can get addicted to other drugs. You may act like you're addicted, or lose your inhibition and use it to excess because you like being high (or become pseudo-dependent on it if you're actually depressed and using it in place of an SSRI since you don't naturally make enough serotonin...), but you won't actually get hurt if you suddenly stop using it.
Some Parting Advice
"Drugs... drugs are bad. Mm'kay? Don't do drugs 'cus drugs are bad." - Mr. MackeyWell, no. Not really. Drugs aren't inherently bad, but they're dangerous. We simply aren't built to consume of massive amounts of foreign psychotropics. Our species "grew up" in such a way that allows us to not die every time we stick something new in our bodies. We handle it, and sometimes it gets us high, or relaxed, or happy, or what-have-you, but users are still risking injury, addiction, and death. (Not to mention all these chemical issues are also being complimented by the things we went over in the "behavioral addiction" installment of this series.)
If you're going to do drugs, especially if you're going to do them on a regular basis. Be smart, be safe, and don't act like a freaking moron and think you're somehow immune to all this. You're not.