The term "addiction" refers to a compulsion to do something, either a substance or an activity, over and over again, regardless of the consequences. For example, a nicotine addict will continue to smoke even after they have been diagnosed with emphysema or cancer. Or a cocaine addict will continue to use the drug even after being arrested buying coke in a bad neighborhood.

Addiction can happen in two ways -- physically or psychologically. With a physical dependence, the user will suffer physical withdrawal symptoms when he or she stops using the drug. This is most common with opiates, like narcotic pain relievers or heroin. Other substances that can induce physical symptoms on withdrawal are alcohol, barbiturates (some older types of sleeping pills), nicotine and benzodiazepines (xanax, valium, ativan, etc.) Sometimes the withdrawal symptoms can cause serious seizures, as in the case with benzos. People with a physical dependency on a substance will take it, not to obtain pleasure after a point, but simply to relieve withdrawal symptoms. Physical dependency is sometimes referred to as physiological tolerance.

Psychological addiction is different in that a user will use a substance more for the pleasure that they initially get from it more than anything else. The substance will usually interact with the person's brain chemistry and release pleasure inducing chemicals that enforce the use of the drug. This becomes a self perpetuating pattern that the addict finds very hard to stop. The brain chemicals involved in this are usually dopamine, serotonin and associated endorphins. Let's use cocaine as an example. The user will take some cocaine, which in turn will raise the level of dopamine in the brain creating intense pleasure. But what comes up must come down, so when the drug wears off, the user will feel down or depressed and therefore feel compelled to repeat the cycle.

Once this cycle is started it will take more and more of the substance to produce the desired effect as the brain adapts to the drug. The brain chemistry will change and the user will never be able to get as "high" as they did the first few times they used the substance and they spend the rest of their time "chasing" that high to no avail. With continued heavy usage the good effects of the drug will go away and the negative effects will be what the user experiences.

It's not just drugs that people can become addicted to. Activities such as gambling, surfing the Internet, sex, looking at porn, work and even healthy activities such as exercise can also help produce the endorphins in the brain that trigger addictive patterns of behavior.

If you or a person you love has a suspected addiction and wants to stop it, you should seek medical help. Sometimes just realizing you have become dependent on a substance or behavior is enough for a person to make the changes needed to kick the habit. Other times more aggressive options are needed, like participation in a twelve-step program, or a stay in rehab can help the person stay clean. The most important thing in getting over an addiction is support and staying away from people and activities that can trigger usage again. With willpower and hard work addictions CAN be overcome.