The DSM-IV (American Psychiatric Association, 1994) defines panic disorder as the spontaneous, unexpected occurrence of panic attacks followed by persistent concern, worry, and anxiety about having additional panic attacks. Panic attacks are defined as a discrete period of intense fear or discomfort in which at least 4 of 13 symptom criteria are met that develop abruptly and reach a peak within 10 minutes. Some of these criteria include cardiac palpitations, sweating, feelings of choking, fear of losing control, and fear of dying. Panic disorder is divided into panic disorder with or without accompanying agoraphobia. However, agoraphobia can also occur without panic disorder, and panic attacks can occur in the absence of panic disorder. Comorbidity with depressive and addictive disorders is frequent.
Barlow et al. (1994) and Smoller and Tsuang (1998) noted that because the diagnostic criteria remain purely clinical, the nosology of anxiety disorders, such as panic disorder, is controversial and evolving. Therefore, it is difficult to do genetic studies because of the difficulty in delineating overlapping phenotypes within the broader context of anxiety disorders. For example, there may be overlap of panic with specific phobias, variable expressivity of panic and anxiety or depression, or phenocopies within a family. The terms 'anxiety neurosis' and 'phobic neurosis' were used in the past (before the DSM-III in 1980) to encompass all of these disorders. Smoller and Tsuang (1998) suggested that dimensional personality traits, such as shyness, behavioral inhibition, and neuroticism (see 607834), could be used to define an anxiety phenotype.
Schumacher et al. (2011) provided a review of the genetics of panic disorder. They noted that there is high (80%) comorbidity with other psychiatric disorders, including agoraphobia, mood disorders, substance abuse, and other anxiety disorders. Associated personality traits include anxiety sensitivity, behavioral inhibition, neuroticism, and harm avoidance. Women are more susceptible to development of the disorder, which has an average age of onset at 23.6 years.
Genetic Heterogeneity of Susceptibility to Panic Disorder
Susceptibility to panic disorder-1 (PAND1) has been mapped to chromosome 13q. See also PAND2 (607853), mapped to chromosome 9, and PAND3 (609985), mapped to chromosome 4. [from
OMIM]