M.D. This is a controversial subject that has divided research and treatment of panic disorder. All human behavior has a biological basis at the nerve cell level, but panic disorder also involves distorted thought and behavior patterns. These areas are the brain stem, limbic system, and frontal cortex, respectively. Panic attacks are triggered by stimulation of areas in the brain stem that control the release of adrenalin. Stimulation of the locus ceruleus produces most of the physical symptoms of panic.
Antidepressants seem to block panic attacks by reducing the firing rate of the locus ceruleus.
The brain stem is also stimulated by higher brain areas which may be involved with stress. The limbic system, involved with the emotions of rage, arousal and fear, is suspected to be the location for anticipatory anxiety. This area is rich with benzodiazepine receptors so benzodiazepine medications are most effective in the limbic area. Paths linking the brain stem with the limbic system can produce anticipatory anxiety following a panic attack and vice versa. The limbic system is also sensitive to changes in blood flow caused by hyperventilation.