Anxiety symptoms and anxiety disorders are common in community settings and primary and secondary medical care. Anxiety symptoms are often mild and only transient, but many people are troubled by severe symptoms that cause both considerable personal distress and a marked impairment in social and occupational function. The principal anxiety disorders are currently considered to comprise panic disorder, generalised anxiety disorder, social anxiety disorder, agoraphobia, specific phobias, separation anxiety disorder and selective mutism. Additional conditions (not considered further here) include substance/medication-induced anxiety disorder, anxiety disorder due to another medical condition, other specified anxiety disorder and unspecified anxiety disorder. Together, anxiety disorders constitute the most frequent mental disorders, with an estimated 12-month prevalence of approximately 10–14 per cent.

Although the societal impact of anxiety disorders is substantial, many of those who could benefit from psychological or pharmacological treatment are neither recognised nor treated. Recognition relies on maintaining a keen awareness of the psychological and physical symptoms of anxiety disorders, and accurate diagnosis rests on identifying the pathognomonic features of specific conditions.