Alcoholics Anonymous One of the earliest forms of addiction treatment in the United States, AA developed the 12-step approach to assisting recovery from alcohol addiction (alcoholism). Several other anonymous groups have adapted the 12-step approach to help people recover from addiction to other drugs (e.g., Narcotics Anonymous, Cocaine Anonymous, Pot Smokers Anonymous).
Alveoli Tiny, balloon-like air sacks in the lungs. Alveoli are designed to allow oxygen to pass rapidly into the blood and are also efficient at absorbing inhaled drugs.
Alzheimer's disease A degenerative disease in which neurons of the brain die, leading to the loss of the ability to think, learn and remember (dementia).
Amino acids Small chemical compounds that are the building blocks of proteins.
Amphetamines Stimulant drugs whose effects are very similar to cocaine.
Analgesics Drugs that relieve pain.
Analogs Drugs whose chemical structures have been slightly modified from a parent compound. There are many analogs to morphine or to LSD. See Designer drug.
Anandamide The endogenous neurotransmitter that binds to the cannabinoid receptor.
Anesthesia The loss of sensation, primarily to pain, often accompanied by the loss of consciousness.
Anesthetic gases Gaseous drugs that produce loss of sensation and consciousness.
Antagonist A chemical that binds to a receptor and blocks it, producing no response, and preventing agonists from binding, or attaching, to the receptor. Antagonists include caffeine and naloxone.
Assessment The diagnostic process in which a professional examines a drug user to determine the extent of the person's drug use, whether he or she is addicted, and what type of treatment might be most effective.
Auditory cortex That part of the cerebral cortex that processes sounds and produces our awareness of them.
Axon The cable-like structure neurons used to send messages to other neurons. It carries the neuron's electrical message.
Axon terminal The structure at the end of an axon that produces and releases chemicals (neurotransmitters) to transmit the neuron's message across the synapse to another neuron.