Systematic desensitization: A behavioral treatment that uses relaxation training and a fear hierarchy to help clients with phobias react calmly to the objects or situations they dread.

Anxiety: The central nervous system’s physiological and emotional response to a vague sense of threat or danger.

Relaxation training: A treatment procedure that teaches clients to relax at will so they can calm themselves in stressful situations.

Phobia: A persistent and unreasonable fear of a particular object, activity, or situation.

Electromyograph (EMG): A device that provides feedback about the level of muscular tension in the body.

Classical conditioning: A process of learning in which two events that repeatedly occur close together in time become tied together in a person’s mind and so produce the same response.

Flooding: A treatment for phobias in which clients are exposed repeatedly and intensively to a feared object and made to see that it is actually harmless.

Exposure treatments: Behavioral treatments in which persons are exposed to the objects or situations they dread.

Sedative-hypnotic drugs: Drugs used in low doses to calm people and in higher doses to help people sleep. Also called anxiolytic drugs.

Specific phobia: A severe and persistent fear of a specific object or situation (does not include agoraphobia and social anxiety disorder).

Fear: The central nervous system’s physiological and emotional response to a serious threat to one’s well-being.

Modeling: A process of learning in which a person acquires responses by observing and imitating others. Also, a therapy approach based on the same principle.

Stimulus generalization: A phenomenon in which responses to one stimulus are also produced by similar stimuli.

Biofeedback: A technique in which a client is given information about physiological reactions as they occur and learns to control the reactions voluntarily.

Rational-emotive therapy: A cognitive therapy developed by Albert Ellis that helps clients identify and change the irrational assumptions and thinking that help cause their psychological disorder.

Preparedness: A predisposition to develop certain fears.

Agoraphobia: An anxiety disorder in which a person is afraid to be in public places or situations from which escape might be difficult (or embarrassing) or help unavailable if panic-like symptoms were to occur.

Client-centered therapy: The humanistic therapy developed by Carl Rogers in which clinicians try to help clients by being accepting, empathizing accurately, and conveying genuineness.

Benzodiazepines: The most common group of antianxiety drugs, which includes Valium and Xanax.

Gamma-aminobutyric acid (GABA): A neurotransmitter whose low activity has been linked to generalized anxiety disorder.

Basic irrational assumptions: The inaccurate and inappropriate beliefs held by people with various psychological problems, according to Albert Ellis.

Locus coeruleus: A small area of the brain that seems to be active in the regulation of emotions. Many of its neurons use norepinephrine.

Social skills training: A therapy approach that helps people learn or improve social skills and assertiveness through role playing and rehearsing of desirable behaviors.

Biological challenge test: A procedure used to produce panic in participants or clients by having them exercise vigorously or perform some other potentially panic-inducing task in the presence of a researcher or therapist.

Anxiety sensitivity: A tendency to focus on one’s bodily sensations, assess them illogically, and interpret them as harmful.

Caudate nuclei: Structures in the brain, within the region known as the basal ganglia, that help convert sensory information into thoughts and actions.

Excoriation disorder: A disorder in which persons repeatedly pick at their skin, resulting in significant sores or wounds. Also called skin-picking disorder.

Compulsion: A repetitive and rigid behavior or mental act that persons feel driven to perform in order to prevent or reduce anxiety.

Panic attacks: Periodic, short bouts of panic that occur suddenly, reach a peak within minutes, and gradually pass.

Neutralizing: Attempting to eliminate thoughts that one finds unacceptable by thinking or behaving in ways that make up for those thoughts and so put matters right internally.

Stress-management program: An approach to treating generalized and other anxiety disorders that teaches clients techniques for reducing and controlling stress.

Norepinephrine: A neurotransmitter whose abnormal activity is linked to panic disorder and depression.

Social anxiety disorder: A severe and persistent fear of social or performance situations in which embarrassment may occur.

Obsession: A persistent thought, idea, impulse, or image that is experienced repeatedly, feels intrusive, and causes anxiety.

Orbitofrontal cortex: A region of the brain in which impulses involving excretion, sexuality, violence, and other primitive activities normally arise.

Hoarding disorder: A disorder in which people feel compelled to save items and experience significant distress if they try to discard them, resulting in an excessive accumulation of items and possessions.

Body dysmorphic disorder: A disorder in which individuals become preoccupied with the belief that they have certain defects or flaws in their physical appearance. The perceived defects or flaws are imagined or greatly exaggerated.

Trichotillomania: A disorder in which people repeatedly pull out hair from their scalp, eyebrows, eyelashes, or other parts of their body. Also called hair-pulling disorder.

Obsessive-compulsive disorder: A disorder in which a person has recurrent and unwanted thoughts and/or a need to perform repetitive and rigid actions.

Exposure and response prevention: A behavioral treatment for obsessive-compulsive disorder that exposes a client to anxiety-arousing thoughts or situations and then prevents the client from performing his or her compulsive acts. Also called exposure and ritual prevention.

Panic disorder: An anxiety disorder marked by recurrent and unpredictable panic attacks.

Serotonin: A neurotransmitter whose abnormal activity is linked to depression, obsessive-compulsive disorder, and eating disorders.