Diagnostic Markers
Agents with disparate mechanisms of action, such as sodium lactate, caffeine, isoprotere-
nol, yohimbine, carbon dioxide, and cholecys tokinin, provoke panic attacks in individuals
with panic disorder to a much greater extent than in healthy control subjects (and in some
cases, than in individuals with other anxiet y, depressive, or bipo lar disorders without
panic attacks). Also, for a proportion of indi viduals with panic disorder, panic attacks are
related to hypersensitive medullary carbon di oxide detectors, resulting in hypocapnia and
other respiratory irregularities . However, none of these labo ratory findings are consid-
ered diagnostic of panic disorder.
Suicide Risk
Panic attacks and a diagnosis of panic disorder in the past 12 months are related to a higher
rate of suicide attempts and suicidal ideation in the past 12 months even when comorbid-
ity and a history of childhood abuse and other suicide risk factors are taken into account.
Functional Consequences of Panic Disorder
Panic disorder is associated with high levels of social, occupational, and physical disabil-
ity; considerable economic co sts; and the highest number of medical visits among the anx-
iety disorders, although the effects are st rongest with the presence of agoraphobia.
Individuals with panic disorder may be freque ntly absent from work or school for doctor
and emergency room visits, which can lead to  unemployment or dropping out of school.
In older adults, impairment may be seen in caregiving duties or volunteer activities. Full-
symptom panic attacks typically are associated with greater morbidity (e.g., greater health
care utilization, more disabilit y, poorer quality of  life) than limited-symptom attacks. 
Differential Diagnosis
Other specified anxiety disorder or unspecified anxiety disorder. Panic disorder should