Addiction: A chronic, relapsing disease characterized by compulsive drug seeking and use, despite serious adverse consequences, and by long-lasting changes in the brain.
Agonist: A chemical entity that binds to a receptor and activates it, mimicking the action of the natural (or abused) substance that binds there.
Antagonist: A chemical entity that binds to a receptor and blocks its activation. Antagonists prevent the natural (or abused) substance from activating its receptor.
Barbiturate: A type of CNS depressant prescribed to promote sleep (usually in surgical procedures) or as an anticonvulsant.
Benzodiazepine: A type of CNS depressant prescribed to relieve anxiety and sleep problems. Valium and Xanax are among the most widely prescribed medications.
Buprenorphine: A mixed opiate agonist/antagonist medication approved by the FDA in October 2002 for the treatment of opioid addiction (e.g., heroin).
Central Nervous System: The brain and spinal cord.
CNS Depressants: A class of drugs that slow CNS function (also called sedatives and tranquilizers), some of which are used to treat anxiety and sleep disorders; includes barbiturates and benzodiazepines.
Comorbidity: The occurrence of two disorders or illnesses in the same person, also referred to as co-occurring conditions or dual diagnosis. Patients with comorbid illnesses may experience a more severe illness course and require treatment for each or all conditions.
Detoxification: A process in which the body rids itself of a drug (or its metabolites). During this period, withdrawal symptoms can emerge that may require medical treatment. This is often the first step in drug abuse treatment.
Dopamine: A brain chemical, classified as a neurotransmitter, found in regions that regulate movement, emotion, motivation, and pleasure.
Methadone: A long-acting synthetic opioid medication that is effective in treating opioid addiction and pain.
Narcolepsy: A disorder characterized by uncontrollable episodes of deep sleep.
Norepinephrine: A neurotransmitter present in the brain and the peripheral (sympathetic) nervous system; and a hormone released by the adrenal glands. Norepinephrine is involved in attention, responses to stress, and it regulates smooth muscle contraction, heart rate, and blood pressure.
Opioid: A compound or drug that binds to receptors in the brain involved in the control of pain and other functions (e.g., morphine, heroin, hydrocodone, oxycodone).
Physical Dependence: An adaptive physiological state that occurs with regular drug use and results in a withdrawal syndrome when drug use is stopped; often occurs with tolerance. Physical dependence can happen with chronic—even appropriate—use of many medications, and by itself does not constitute addiction.
Polydrug Abuse: The abuse of two or more drugs at the same time, such as CNS depressants and alcohol.
Prescription Drug Abuse: The use of a medication without a prescription; in a way other than as prescribed; or for the experience or feeling elicited. This term is used interchangeably with "nonmedical" use, a term employed by many of the national surveys.
Psychotherapeutics: Drugs that have an effect on the function of the brain and that often are used to treat psychiatric/neurologic disorders; includes opioids, CNS depressants, and stimulants.
Respiratory Depression: Slowing of respiration (breathing) that results in the reduced availability of oxygen to vital organs.
Sedatives: Drugs that suppress anxiety and promote sleep; the NSDUH classification includes benzodiazepines, barbiturates, and other types of CNS depressants.
Stimulants: A class of drugs that enhances the activity of monamines (such as dopamine) in the brain, increasing arousal, heart rate, blood pressure, and respiration, and decreasing appetite; includes some medications used to treat attention-deficit hyperactivity disorder (e.g., methylphenidate and amphetamines), as well as cocaine and methamphetamine.
Tolerance: A condition in which higher doses of a drug are required to produce the same effect achieved during initial use; often associated with physical dependence.
Tranquilizers: Drugs prescribed to promote sleep or reduce anxiety; the NSDUH classification includes benzodiazepines, barbiturates, and other types of CNS depressants.
Withdrawal: Symptoms that occur after chronic use of a drug is reduced abruptly or stopped.
This series of reports simplifies the science of research findings for the educated lay public, legislators, educational groups, and practitioners. The series reports on research findings of national interest.
Please note: After September 2013 all NIDA Research Reports will be offered online exclusively. Orders for printed hard copies must be received by August 15, 2013.
As a result of scientific research, we know that addiction is a disease that affects both brain and behavior.