How Addiction Works

We become addicted to a substance or activity for the same reason that we initially try it: Because we like the way it makes us feel. And although some people may try a drug, take a drink or eat a donut and never become hooked, almost all of us have the capability to become addicted. Users cross a threshold and undergo a transition to addiction.

Research has shone light on the changes that take place in the brain after this transition, developing the "brain disease" model of addiction. It's currently the most widely held view of addiction among the scientific community.

The way we learn to survive is based on a reward system. When we do something that aids in our survival, like eating or exercising, our brain's limbic system rewards us for this behavior by releasing dopamine, a chemical that makes us feel good. Since we like the way we feel, we learn to repeat the behavior.

Different substances approach the limbic system -- the reward center -- in our brains in different ways, but all substances of abuse cause the brain to release high levels of dopamine. This release can be two to 10 times the amount our brain releases normally, giving the user a sense of a "rush" or "high."

Because of this release and its impact on the brain's reward center, users learn very quickly to use a substance or engage in an activity. They learn this in the same way they learn to eat or exercise, but even faster and with more intensity, since the release of dopamine is so much larger. Since the amount of dopamine released is abnormal, the brain struggles to regain its normal chemical balance after a substance wears off. This produces a hangover, or withdrawal, from a substance, which can manifest in physical pain, depression and even dangerous behavior.

Over time, prolonged use of a substance can lead the brain to stop producing as much dopamine as it naturally does. This creates further withdrawal, leading to a physical dependency -- the addict needs to use more of the substance just to feel normal, creating a vicious cycle that can be difficult to break.

Because of this learning process and eventual physical dependence on a substance, the substance user becomes a substance abuser. As a result, the abuser loses control over the act of taking a substance or engaging in an activity. This has led to the idea that in order to cure an addiction, abstinence -- total discontinuation of substance use or behavior -- is necessary.

Under the disease model of addiction, the brain's motivational center becomes reorganized. The priorities are shuffled so that finding and using the substance (or another substance that will produce similar effects) becomes top priority as far as the brain is concerned. In this sense, the drug has essentially taken over the brain, and the addict is no longer in control of his behavior. An alcoholic won't, for example, have trouble deciding whether or not to get in his car and drive to the store to get more alcohol -- the urge will be irresistible.

But simply going to the store to buy alcohol is not a definitive sign of alcoholism. So how can you tell the difference between using a substance and being addicted to it? In the next section, we'll learn about the symptoms of addiction.

Through extensive study of addicts and what makes them tick, science has narrowed down behaviors and traits that are symptoms of addiction. These symptoms are divided into two types: physical and behavioral.

Compulsive behavior, like a sex or gambling addiction, relate only to behavioral symptoms. But substance abuse can include both types:

Taken together, these symptoms constitute addiction. In conjunction with the "brain disease" model, these symptoms of addiction have created the view that addiction is a chronic disease, just like asthma. Based on this, researchers have determined that addicted people, like asthma sufferers, may experience relapses and that rehab programs for addiction should include "booster sessions."

While these are the symptoms of addiction, it has been shown that some people are more susceptible than others to falling prey to it. It has been long-held that initial drug use is a voluntary act, but behavioral psychologists point out that isn't necessarily the case. There are a variety of risk factors that have been identified which can lead a person into addiction. Variables like genetics (more on that coming up), peer pressure, existing psychological disorders, anxiety and depression and the quality of a person's home life can all lead him to becoming addicted to a substance or behavior.

A person who is depressed, for example, may try drugs in an attempt to self-medicate, or he may engage in sexual behavior to try to improve his sense of self-worth. Both of these behaviors can lead to an addiction to the substance or behavior. In the next section, we'll look at a few of the substances and behaviors people can become addicted to.­ ­­

Different substances produce different levels of highs, hangovers, addictions and cravings. Some will produce few physical withdrawals but strong cravings. Others can do just the opposite. Some addiction researchers have concluded that psychological dependence is the more extreme of the two, as it has more widespread consequences for both the person (by destroying personal relationships) and society at large (through crime committed to get drugs).

There are a wide variety of substances that a person can become addicted to. In 21st-century America, some of the worst and most often used drugs are:

It's not just substances that a person can become addicted to. Behaviors like eating and sex can become compulsive in some people. Although someone addicted to a behavior experiences the same flux of dopamine, when the compulsive behavior is stopped, he will not experience physical symptoms like a substance abuser. Still, the effects compulsive addictions can have on a person's life can be just as devastating. Some of the most common compulsive behaviors are:

In the next section, we'll learn what science is doing to fight addiction.

Research continues to investigate ways to break the addictive cycle. Genetics is among the most cutting-edge investigation being carried out today into the nature of addiction. So far, this research has yielded lots of information on addiction on the genetic level and in brain processes. Researchers have managed to isolate a number of genes, hormones and chemicals in the brain that are directly related to certain types of addictions. By identifying these aspects of addiction, researchers have formed the basis that could lead to the creation of drugs that treat specific addiction.

However, geneticists aren't betting that they will find a single gene that leads to addiction in people. Research so far has shown that genetic predisposition is most likely caused by a combination of genes working together. Interestingly, research has shown that genes also play a role in making people less susceptible to addiction. Rather than simply not having genes that would make them more likely to become addicted to a substance, some people actually have genes that can keep them from ever becoming addicted.

There are already some medications in use that can treat addiction or alleviate symptoms. For many years, methadone has been used to treat heroin addiction. This drug affects the opiate receptors, and can alleviate both the physical and psychological symptoms of withdrawal. Another drug that has shown promise for treating heroin addiction, LAAM (levo-alpha-acetyl methadol), acts as an opioid antagonist, keeping opiate receptors in the brain from being stimulated, thus degrading the effect heroin has on the user.

Another prescription medication, Nalmefene, has been shown to curb gambling addiction. It's also being tested to see if it can cure alcoholism, but has shown weaker results than it has in treating gambling addiction.

The most widespread medications used to treat addiction are antidepressants. These drugs address the feelings of despair that can result from psychological dependency. They can also help treat any preexisting condition, like depression, that may have led to the addiction in the first place.

This is a good example of the holistic approach that science is currently undertaking to treat addiction. This holistic approach identifies the need to address not only the brain disease of addiction, but also the internal factors (such as genetics) and the external risk factors that lead to and enable addiction. Addiction is a multifaceted chronic disease, and it takes multifaceted treatment to restore the life of the addict to normalcy.

For more information on addiction and related topics, check out the links on the next page.