The definition of substance abuse is the overindulgence in and dependence on an addictive substance, such as drugs or alcohol. One of the common misconceptions revolving around information on substance abuse is that drug addiction is considered a disease. This theory turns the addict into a poor sick person that can’t do anything about his addiction disease. Nothing can be further from the truth, as the addict does not have a disease; he is addicted. Not at any time before an illness does the person about to become sick have a choice of saying yes or no to the disease he is about to become ill with. However, when a person becomes addicted to a substance, he, at some point in the addiction process had a choice. The very first time a person used a drug, he had the choice of saying yes or no. If he is now addicted, evidently he did not say no.
One substance that is very high addictive is methamphetamine. Meth, which stimulates the central nervous system can be swallowed, snorted, 
smoked, or injected into a vein. Meth use triggers both acute and chronic responses. Rapid and intense mood swings from friendly to extremely hostile are common. The drug can also cause irritability, violence, extreme paranoia, and hallucinations, as well as confusion and memory loss. The addict uses this drug to stay up for days at a time, then, several hours after the last use, he is overcome by such a numbing exhaustion that he may sleep for days. After a deep sleep, he is usually depressed upon waking.
With chronic use, the brain levels of both dopamine* and serotonin* go down, and may not return to normal for one to four years. Permanent neurological damage may result with extended use.
After trying drugs, a person may think he is getting positive results from his drug use. After some time passes, the drugs no longer make the user feel and do better. In fact, the user begins to have to use more and more drugs, not to feel better, but just to try to feel normal. The drugs actually take over the user’s life. At this point, the addict has trouble learning and remembering anything new, he has trouble when making a decision; and his judgment seems to be warped.
The body now has a physical addiction to drugs, and the addict’s only thought is to get more drugs. At this stage, it is extremely difficult for an addict to stop using drugs without some sort of help through both rehab and counseling. The addict must be taught how to change the entire structure of his life and learn to live without drugs.
dopamine: a substance in the body acting within the brain to help regulate movement and emotion.
serotonin: another substance in the body involved in sleep, depression, memory, and other processes dealing with nerves and logic.
