Here is a list of terms that you should become familiar with, a more complete list can be found here.
Abuse – Excessive use of a substance in a way it was not meant to be used or not as prescribed.
Addiction – A behavioral syndrome characterized by the repeated, compulsive seeking or use of a substance despite adverse social, psychological, and/or physical consequences, and a need for an increased amount of the substance, as time goes on, to achieve the same effect. Addiction is often (but not always) accompanied by physical dependence, a withdrawal syndrome, and tolerance.
Detox – The metabolic process by which the toxic qualities of a poison or toxin are reduced by the body.
Dopamine – Dopamine is a chemical naturally produced in the body. In the brain, dopamine functions as a neurotransmitter which provides feelings of euphoria and well being. Drugs cause a surge in levels of dopamine, which results in feelings of pleasure.
Relapse – A relapse occurs when a person is affected again by a condition that affected them in the past. This could be a medical condition such as depression, bipolar disorder, cancer or an addiction to a drug.
Remission – A period of time in which the signs and symptoms of the addiction have disappeared.
Withdrawal – Withdrawal syndrome consists of a predictable group of signs and symptoms resulting from abrupt removal of, or a rapid decrease in, the regular dosage of a psychoactive substance.