Addiction is a very serious and sensitive subject that is not easy to figure out especially because it changes with each person. Webster's definition is, 1 : The quality or state of being addicted. Addict (ed) 1 : To devote or surrender (oneself) to something habitually or excessively. 2 : compulsive need for and use of a habit-forming substance (as heroin, nicotine, or alcohol) characterized by well-defined physiological symptoms upon withdrawal; also : persistent compulsive use of a substance known by the user to be harmful. To be aware of an addiction is the first step. There are many people who are addicts but don't want to admit it. It's pretty easy to get addicted to something that is not a chemical or drug, for example food. Food is very addicting and is possible to go many days without although when broken down chemicals are present eventually so that doesn't count. Exercise can be very addicting and when use to it the body and mind will go into withdrawals when taken away. watching t.v. can be addicting. I think whatever our mind and body judges as positive or pleasurable we are at risk of getting addicted to. Alcoholics Anonymous and Narcotics Anonymous sees addiction as uncontrollable and that we are defenseless against it. They also bring God into their 12 steps principles which I will try to leave out as much as possible. Not that I don't believe in God or a higher power, cause I do, but it tends to turn people off to talk about religion or God when explaining something. Addiction is related to OCD or obsessive compulsive disorder which is a mental illness and a chemical imbalance of the brain and body. To treat the disorder medication and treatment is common. Some people see addiction as a weakness and they're right it really is. How much control we have over it varies by person and is often powerful enough to be considered a disease or sickness. Some of us get so addicted everything else in the world seems to fade as our focus is solely tuned to our addiction. If an illegal substance is the addictive source then the person usually tries to justify the use. They will usually resort to either denying use or just denying addiction to the drug. To admit addiction means admitting to a weakness which is impossible because us humans don't have weaknesses or problems, right? When an addict finds an action or substance he/she likes, repetition of use increases do to a change and balancing of our bodies chemicals. As repetition of use increases our bodies need for that action elevates and increases. As our body intakes the chemical or drug our metabolism tries to sort out the chemicals as fast as possible. This information goes consistent with the alcoholic that can't get enough to drink. His body is constantly trying to use the alcohol to it's advantage one ounce after another. It gets to be a problem when the use or intake becomes to fast and the body starts over reacting and trying to reject the excess chemical in a few different ways. We all know about throwing up. This is the bodies defense against poison that enters it. A reason we try drinking or using a chemical like alcohol is our body reacts to the substance in a positive way at first, but sometimes experimentation leads to repetitive use which eventually leads to dependence. Dependence is usually seen as a bad thing because of the withdrawals that follow when the that need is not satisfied or usage is stopped.  A good article on the after effects of meth addicts is at:

www.nida.nih.gov/Testimony/3-14-01Testimony.html

The article shows PET scans of how a meth addicts brain is functioning and how it differs from a "normal" persons brain. This evidence is proof that addiction is not just a psychological disability but a physical one as well. The article also goes into how this difference is repairable like any other chemical imbalance of the brain and body.