The vestibular system consists of three semi-circular canals filled with liquid and two "otoliths" that are located in the inner ear. These structure tell us how we are positioned and space and allow us to judge how we are moving through space. Malfunctions of the vestibular system can cause vertigo, nausea, dizziness and inability to balance. Levinson suggests that vestibular disfunction may predispose people to develop many kinds of phobia.
TITLE: A cerebellar-vestibular explanation for fears/phobias: hypothesis and study
AUTHOR: Levinson HN
JOURNAL: Perceptual and Motor Skills. 1989 Feb;68(1):67-84.
ABSTRACT: "To clarify and test the cerebellar-vestibular (CV) basis of fears/phobias, responses of 4000 learning disabled children, adolescents, and adults with neurological and electronystagmographic (ENG) evidence of CV-dysfunction were analyzed for anxiety-related symptoms. Of this sample, 64.6% indicated fears/phobias; females were significantly more predisposed; mixed-handedness was significantly related to fears of heights and reduced vestibular response or asymmetric vestibular functioning. Also, adults had a higher incidence of the specific fears/phobias characterizing agoraphobia than children and adolescents. Analysis of factors reported as triggering the fears/phobias led to (1) a classification and theory of fears/phobias, obsessions/compulsions, and related anxiety symptoms based on realistic or traumatic, neurotic, and CV- or other CNS-based mechanisms rather than on DSM-III--R surface descriptions; (2) an understanding of the relationships between mitral valve prolapse, agoraphobia and panic episodes, as well as depression; and (3) new insights into differential diagnosis and selective treatment." [full text]
The sample used in this study are not a normal cross-section of the population, but a large group of learning disabled individuals--a group where vestibular problems are more common. And the study does not have a control group which greatly limits the conclusions that can be drawn.
However it is interesting to note that anti-motion sickness medications which help stabilise the vestibular system and improve its function, seemed to help this group with their phobias.
riving anxiety was reported by 4.9% of the adults in the group, and 2% of the overall group (including children and adolescents who are less likely to be driving). The paper assesses phobias and vestibular function but does not seem to (be able to?) assess the correlation between the two and so is ultimately more suggestive than informative. However there does seem to be some grounds for suggesting that vestibular disfunction may be a predisposing factor for developing phobias including driving anxiety.