The underlying biological cause of panic attacks is not known. However, researchers theorize that it involves abnormalities in the areas of the brain responsible for interpreting potential threats, such as the amygdala (the brain's "fear center"), locus ceruleus (area of the brainstem that helps determine which stimuli are worth paying attention to), and hippocampus (plays a central role in processing long-term memories). Imbalances of the neurotransmitters norepinephrine and serotonin may also play a role.
People with a current or past anxiety or mood disorder are at greater risk for panic attacks. Use of stimulants, such as methylphenidate (Ritalin), caffeine, or cocaine, can also promote panic attacks.