Glossary

Plain-language definitions of the terms you meet in psychiatric medication information.

A

Antidepressant

A medication used to treat depression, and often anxiety and related conditions. Most antidepressants take several weeks to reach their full effect.

B

Benzodiazepine

A class of fast-acting sedative medications used for anxiety and panic. They work quickly but carry a risk of dependence, so they are usually used short-term.

Boxed warning

The strongest safety warning the U.S. Food and Drug Administration requires on a medication's labeling. It highlights a serious risk, but it does not mean the medication is unsafe for everyone. Also called a black box warning.

C

Contraindication

A specific situation or condition in which a medication should not be used because the risk is too high.

D

Discontinuation syndrome

Temporary symptoms, such as dizziness, flu-like feelings, irritability, and brief electrical "brain zap" sensations, that can follow stopping an antidepressant too quickly. A gradual taper usually prevents it.

Dopamine

A chemical messenger in the brain involved in motivation, focus, and reward.

F

First-line

The treatment a clinician usually tries first for a condition, based on the balance of evidence, effectiveness, and safety.

G

GABA

The brain's main calming, or inhibitory, chemical messenger. Several anti-anxiety medications work by strengthening its effect.

Generalized anxiety disorder (GAD)

A condition involving persistent, excessive worry across many areas of life, lasting for months.

Generic

A medication sold under its chemical name rather than a brand name. A generic contains the same active medication as the brand and works the same way, usually at a much lower price.

H

Half-life

The time it takes for the level of a medication in the body to fall by half. A longer half-life means a drug clears more slowly, which affects how often it is taken and how it feels to stop.

Hyponatremia

A lower-than-normal level of sodium in the blood. It is an uncommon side effect of some antidepressants, and is more likely in older adults.

M

MAOI

Monoamine oxidase inhibitor, an older class of antidepressant. MAOIs interact dangerously with many drugs and some foods, so they need careful separation in time from other antidepressants.

Mood stabilizer

A medication used to even out mood, used mainly in bipolar disorder. Examples include lithium and lamotrigine.

N

NDRI

Norepinephrine-dopamine reuptake inhibitor, the class bupropion belongs to. It works on norepinephrine and dopamine rather than serotonin.

Norepinephrine

A chemical messenger involved in alertness, energy, and the body's stress response.

O

Obsessive-compulsive disorder (OCD)

A condition involving intrusive, unwanted thoughts, called obsessions, and repetitive behaviors, called compulsions, done to ease them.

Off-label

The use of a medication for a purpose the FDA label does not formally list. Off-label prescribing is legal and common when evidence and clinical experience support it.

P

Panic disorder

A condition involving repeated, unexpected panic attacks and ongoing worry about having more of them.

Physical dependence

When the body has adjusted to a medication so that stopping it suddenly causes withdrawal symptoms. It can happen with prescribed use and is not the same as addiction.

Premenstrual dysphoric disorder (PMDD)

A severe form of premenstrual symptoms involving significant mood changes in the days before a period.

Q

QT prolongation

A change in the heart's electrical rhythm that some medications can cause. It is usually measured with an ECG and matters most at higher doses or with certain heart conditions.

R

Reuptake

The process by which a nerve cell reabsorbs a chemical messenger it has released. Many psychiatric medications work by slowing reuptake so more of the messenger stays available.

S

Serotonin

A chemical messenger involved in mood, sleep, appetite, and anxiety. Many antidepressants act on serotonin.

Serotonin syndrome

A rare but serious reaction caused by too much serotonin activity, usually from combining serotonergic drugs. It is a medical emergency.

SNRI

Serotonin-norepinephrine reuptake inhibitor, a class of antidepressant that acts on both serotonin and norepinephrine. Examples include venlafaxine and duloxetine.

SSRI

Selective serotonin reuptake inhibitor, the most commonly prescribed class of antidepressant. SSRIs are used for depression and many anxiety conditions.

T

Taper

Reducing a medication's dose gradually, in steps, rather than stopping all at once, so the body can adjust.

Titration

Adjusting a medication's dose gradually, up or down, to find the amount that works best with the fewest side effects.

Tolerance

When the body adapts to a medication so that the same dose has less effect over time. It is a particular concern with benzodiazepines.

Treatment-resistant depression

Depression that has not improved enough after two or more adequate courses of antidepressant treatment.

W

Withdrawal

Symptoms that appear when a medication the body has become dependent on is reduced or stopped. With some medications, withdrawal can be serious and needs medical supervision.