Q. I am doing research into the causes of panic disorder and also into agoraphobia. One theory I am working on involves sensory overload. Toward this end, I was wondering if you knew of any studies involving the prevalence of the blind/hearing impaired who suffer from panic disorder and/or agoraphobia. Thanks for your help.

A. There are many theories as to the causes of panic disorder, but none has been conclusively proven. (For a good general review, see the chapter by Pine et al in the book, "Pharmacotherapy for Mood, Anxiety, and Cognitive Disorders", edited by Halbreich & Montgomery (American Psychiatric Press, 2000). Much of the research has focused on abnormal "noaradrenergic" activity; i.e., abnormal function in neuronal systems using the neurotransmitter noradrenaline (norepinephrine). Of course, this would not be inconsistent with your hypothesis of "sensory overload".

I am not aware of any studies looking specifically at hearing or visual impairment in panic disorder patients. However, Jacob et al looked at auditory function in patients with panic disorder and agoraphobia with panic attacks (Am J Psychiatry 1985 Jun;142(6):715-20). A battery of vestibular and audiological tests was administered to eight patients with panic disorder and 13 patients with agoraphobia and panic attacks, all of whom experienced dizziness during their panic attacks. Positional or spontaneous nystagmus was present in 67% of the subjects. Abnormal responses were found in caloric testing (56%), rotational testing (35%), and posturography (32%). Pure tone audiograms were abnormal in 26% of the subjects and acoustic reflexes were abnormal in 44% of the subjects. Six of eight patients tested had an abnormal brainstem auditory evoked potential.

Because there was no control group, it's hard to know if these abnormalities are specific to panic disorder patients, or what relation they have with actual panic symptoms. Still, it may open up some possibilities with respect to your hypothesis. On the other hand, Roy-Byrne et al (Psychiatry Res 1985 Jan;14(1):77-84) found normal pain sensitivity in patients with panic disorder, which might argue against a "sensory overload" hypothesis (depending on the specifics).

August 2001

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