Exposure therapy for anxiety disorders: theoretical mechanisms of exposure and treatment strategies
Over a quarter of the people in the US population will have an anxiety disorder sometime during their lifetime. (1) It is well established that exposure-based behavior therapies are effective treatments for these disorders; unfortunately, only a small percentage of patients are treated with exposure therapy. (2,3) For example, in the Harvard/Brown Anxiety Research Project, only 23% of treated patients reported receiving even occasional imaginal exposure and only 19% had received even occasional in vivo exposure. (4) In part, this may be a lack of well-trained professionals, because most mental health clinicians do not receive specialized training in exposure-based therapies. (5,6)
Another factor may be that many health care professionals do not understand the principles of exposure or may even hold (usually unfounded) negative beliefs about this form of treatment. Surveys of psychologists who treat patients with PTSD show that the majority do not use exposure therapy and most believe that exposure therapy is likely to exacerbate symptoms. (7,8) However, individuals with trauma histories and PTSD express a preference for exposure therapy over other treatments. (9) Furthermore, exposure therapy does not appear to lead to symptom exacerbation or treatment discontinuation. (10) Indeed, a wealth of evidence indicates that exposure-based therapy is associated with improved symptomatic and functional outcomes for patients with PTSD. (11)
The available research literature suggests that exposure-based therapy should be considered the first-line treatment for a variety of anxiety disorders. Here we review a handful of the most influential studies that demonstrate the efficacy of exposure therapy. We also discuss theoretical mechanisms, practical applications, and empirical support for this treatment and provide practical guidelines for clinicians who wish to use exposure therapy and empirical evidence to guide their decision making.
Exposure therapy is defined as any treatment that encourages the systematic confrontation of feared stimuli, which can be external (eg, feared objects, activities, situations) or internal (eg, feared thoughts, physical sensations). The aim of exposure therapy is to reduce the person's fearful reaction to the stimulus.
Graded exposure vs flooding
Most exposure therapists use a graded approach in which mildly feared stimuli are targeted first, followed by more strongly feared stimuli. This approach involves constructing an exposure hierarchy in which feared stimuli are ranked according to their anticipated fear reaction (Table 1). Traditionally, higher-level exposures are not attempted until the patient's fear subsides for the lower-level exposure. By contrast, some therapists have used flooding, in which the most difficult stimuli are addressed from the beginning of treatment (an older variant, implosive therapy, is not discussed in this article). In clinical practice, these approaches appear equally effective; however, most patients and clinicians choose a graded approach because of the personal comfort level. (12,13)
In vivo vs imaginal
In vivo exposure refers to real-world confrontation of feared stimuli. Sometimes, in vivo exposure is not feasible (eg, it would be both difficult and hazardous for someone with combat-related PTSD to experience the sights, sounds, and smells of combat in real life). In such cases, imaginal exposure can be a useful...