Generalised anxiety disorder (GAD) is 1 of a range of anxiety disorders that includes panic disorder (with and without agoraphobia), post-traumatic stress disorder, obsessive–compulsive disorder, social phobia, specific phobias (for example, of spiders) and acute stress disorder. Anxiety disorders can exist in isolation but more commonly occur with other anxiety and depressive disorders. This guideline covers both 'pure' GAD, in which no comorbidities are present, and the more typical presentation of GAD comorbid with other anxiety and depressive disorders in which GAD is the primary diagnosis.

GAD is a common disorder, of which the central feature is excessive worry about a number of different events associated with heightened tension. A formal diagnosis using the DSM‑IV classification system requires 2 major symptoms (excessive anxiety and worry about a number of events and activities, and difficulty controlling the worry) and 3 or more additional symptoms from a list of 6 (see the American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, 4th edition). Symptoms should be present for at least 6 months and should cause clinically significant distress or impairment in social, occupational or other important areas of functioning.

According to the DSM‑IV‑TR, a fundamental characteristic of panic disorder is the presence of recurring, unforeseen panic attacks followed by at least 1 month of persistent worry about having another panic attack and concern about the consequences of a panic attack, or a significant change in behaviour related to the attacks (see the American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision). At least 2 unexpected panic attacks are necessary for diagnosis and the attacks should not be accounted for by the use of a substance, a general medical condition or another psychological problem. Panic disorder can be diagnosed with or without agoraphobia.

GAD and panic disorder vary in severity and complexity and this has implications for response to treatment. Therefore, it is important to consider symptom severity, duration, degree of distress, functional impairment, personal history and comorbidities when undertaking a diagnostic assessment.

GAD and panic disorder can follow both chronic and remitting courses. Where possible, the goal of an intervention should be complete relief of symptoms (remission), which is associated with better functioning and a lower likelihood of relapse.

The guideline assumes that prescribers will use a drug's summary of product characteristics (SPC) to inform their decisions made with individual service users.

This guideline recommends some drugs for indications for which they do not have a UK marketing authorisation at the date of publication, if there is good evidence to support that use. Where recommendations have been made for the use of drugs outside their licensed indications ('off-label use'), this is indicated in the recommendation.

New and updated recommendations are included on the management of generalised anxiety disorder in adults.