Heterogeneity among specific phobia types in DSM-IV.

Recently, it has been suggested that situational specific phobias (e.g., phobias of driving, flying, enclosed places) are more closely related to agoraphobia than are other specific phobia types. The present study investigated this hypothesis by examining heterogeneity among the four main DSM-IV specific phobia types, particularly with respect to variables believed to be associated with agoraphobia. Using interviews and behavioral testing, 60 patients with specific phobias of animals, heights, blood/injections, or driving were compared with respect to etiology, age of onset, physiological response, predictability of panic attacks, and focus of apprehension. Fifteen patients suffering from panic disorder with agoraphobia served as a comparison group for some measures. Relative to the other specific phobias, driving phobias were most strongly associated with a later age of onset, similar to that of individuals with agoraphobia. Height phobias were also associated with a late age of onset as well as a more internal focus of apprehension, relative to other groups. Finally, individuals in the blood/injection phobia group reported a more internal focus of apprehension than those in other groups and were the only group to report a history of fainting in the phobic situation. Overall, the results did not support the hypothesis that situational phobias are a variant of agoraphobia. In fact, on several of the variables for which groups did differ, individuals with height phobias (a phobia from the natural environment type) showed a pattern most similar to individuals with agoraphobia. The implications of these results for the classification of specific phobias are discussed.