Phobic disorders

Phobias include agoraphobia, specific or simple phobia and SP (DSM-IV, 1994). Phobias are characterised by persistent and irrational fears of situations, objects, or activities that result in a compelling desire to avoid phobic stimuli. In DSM-III-R, agoraphobia came to be characterised as a secondary complication of panic and distinct from other phobias. In DSM-IV, agoraphobia, by definition, involves fear of panic attacks or limited symptom panic attacks, so the agoraphobic phenotype can no longer be separated from panic. This view is supported by a substantial body of evidence, but it remains controversial ( Widiger et al., 1996 ). The defining feature of PD may instead be the recurrence of unexpected panic attacks and the development of anticipatory anxiety about additional attacks ( Barlow et al., 1994 ). DSM-IV distinguishes the following subtypes of specific phobias: animal type (e.g., spiders, insects), natural environment type (e.g., storms, heights), blood-injection-injury type (e.g., seeing blood, receiving injections) and situational type (e.g., flying, enclosed spaces). The DSM-IV further notes that specific phobias frequently co-occur. In many cases, more than one subtype of specific phobia is present so that specific phobias form a heterogeneous class of anxiety disorders that frequently occur comorbidly. In a study designed to examine the structure of specific phobias, the results showed that specific phobia symptoms clustered into three factors: animal phobia, blood-injection-injury phobia and a third factor combining natural environment and situational phobias ( Frederikson et al., 1996 ). Although the DSM-IV suggests that natural environment and situational phobias are distinct types of specific phobias, the finding that these types loaded on one factor is not surprising. We may note the strong resemblance as “fear of heights” considered as a natural environment phobia comes close to “fear of elevators” and “fear of flying” that belong to the situational phobias. Interestingly, these empirically derived types of specific phobias are largely in keeping with the typology as proposed by DSM-IV. A recent study designed to examine whether specific phobia subtypes can also be found in children confirmed that childhood-specific phobia symptoms indeed cluster into the three subtypes as described by Frederikson et al. and that these subtypes are either inter-correlated or the product of a single higher order factor ( Muris et al., 1999 ). These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.