In this lecture, I'm going to discuss what I'll be talking about for the rest of the week. One of the topics that I'll touch upon is the history of drug abuse and addiction. And this is particularly illuminating because it implies something about our brains and our culture. You'll see what I mean. Drug abuse has been around for a long time, and that suggests something about our native inborn vulnerability to using drugs. Another topic is how serious the drug abuse problem is. We all know it's serious, but I'll be going into some of the details that describe not only the financial cost, but also the misery this problem produces. I'll talk about the various individual drugs that fall into about ten classes or groups. And it's interesting that some of the drugs in these different groups have actions that are quite different from drugs in the others, yet they all produce addiction. What a fascinating and amazing thing to consider and figure out. Now, let's go into further detail about the definition of drug abuse and addiction. As I mentioned earlier, drug abuse or addiction is seeking and taking drugs in spite of personal distress and harmful consequences. The word addiction denotes a more serious and harmful state than the word abuse. I'll often use them interchangeably, except when I need to emphasize the difference. Another phrase that you may hear is drug dependence. This is associated with a state of physiologic need such that physiologic signs occur when you stop taking the drug. An example is the depression that occurs when an addict stops taking cocaine or the diarrhea that happens when an opiate addict stops taking prescription pain killers. I also want to mention the DSM-5, which is the latest official manual for professionals who deal with and diagnose drug use and drug disorders. The DSM-5 is the fifth edition of The Diagnostic and Statistical Manual of Mental Disorders which is published by the American Psychiatric Association. An interesting thing is that this manual does not use the word addiction or dependence, but rather it refers to problematic use of drugs as a substance use disorder or as a substance-induced disorder. These are interesting changes that avoid using the word addict or dependence, which can be stigmatizing. Being labeled an addict, in any circumstance, can prejudice people against you. A substance use disorder, just as we described for abuse and addiction, is a continued use of the drug in spite of problems. The problems can include impairment, risks to your health, and brain changes. On the other hand, substance-induced disorder refers to things caused by the drugs, and these would include intoxication, withdrawal, or other toxic side effects. Note that other behaviours, besides drug use, are included in the DSM, like gambling disorder. With additional scientific studies, other behaviors may be referred to as addictions or addictive-like states and may be included in future editions of the DSM. Now for something important. We have been describing addiction and abuse in terms of the behavior, which is something you do in spite of harmful consequences. But now I want to shift the focus slightly to talk about a brain-based description of drug abuse and addiction. Because the brain is the organ of behavior and drug addiction is a disorder of problematic behavior, then drug abuse or addiction is a brain disorder. As we look at the brains of people who use drugs, we find that drug use is characterized by changes in the chemistry and anatomy of the brain. And some of these changes are dramatic. It's clear that these changes in chemistry and anatomy underlie and are the cause of addictive behavior. A powerful idea is that if we could reverse some of these chemical changes or anatomical changes, then it seems likely that you would have a way to treat, and maybe even cure, drug users of their addictions. The way these changes occur in the brain is by drugs acting at specific molecular sites that re, we refer to as receptors. Different drugs have different molecular sites, and we'll get into that in more detail. The important issue here, right now, is that we can talk about drug abuse and addiction from the perspective of the brain and the physiology of the brain, in addition to the perspective of behavior. This is an important shift in emphasis that will have many benefits and create a view of addiction that will be helpful to us. As we conclude this lecture, I want you to take some time to explore and answer the following questions. When thinking about drug abuse and addiction as a behavior, what are the key behaviors that define this disorder? Next, which bodily organ controls our behavior and, therefore, contains the basic explanations of abuse and addiction? And finally, as you see in this week's discussion question, we want to learn how to find things at various websites. These websites are just loaded with wonderful materials on this topic. So, as an exercise, please visit the National Institute on Drug Abuse and browse this website. You can start by finding the definition of addiction, and then you can pursue various other things that you may be interested in.
