Anxiety disorders are the most common psychiatric illnesses affecting both children and adults. Anxiety disorders may develop from a complex set of risk factors, including genetics, brain chemistry, personality, and life events. Generalised Anxiety Disorder (GAD) is characterised by excessive, unrealistic worry that lasts six months or more; in adults, the anxiety may focus on issues such as health, money, or career. In obsessive-Compulsive Disorder (OCD) individuals are plagued by persistent, recurring thoughts (obsessions) that reflect exaggerated anxiety or fears; typical obsessions include worry about being contaminated or fears of behaving improperly or acting violently. Panic Disorder, a third type of anxiety disorder, is when people suffer severe attacks of panic which may make them feel like they are having a heart attack or are going crazy for no apparent reason. Post-Traumatic Stress Disorder (PTSD) can follow an exposure to a traumatic event such as a sexual or physical assault, witnessing a death, the unexpected death of a loved one, or natural disaster. Social Anxiety Disorder (Social Phobia; SAD) is characterised by extreme anxiety about being judged by others or behaving in a way that might cause embarrassment or ridicule. In regards to specific phobias people with specific phobias suffer from an intense fear reaction to a specific object or situation (such as spiders, dogs, or heights); the level of fear is usually inappropriate to the situation, and is recognised by the sufferer as being irrational. Drugs used to treat anxiety disorders include selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants, benzodiazepines, beta blockers, and monoamine oxidase inhibitors (MAOIs). This new book brings together leading research from throughout the world.