Phobias are often treated with exposure therapy, in which the phobic person is gradually exposed to the situation or thing that they fear. Exposure therapy works to reduce the fear response and form a new set of memory associations that are not associated with fear. The researchers thought that certain effects of the stress hormone cortisol might boost the effectiveness of exposure therapy. Previous research has found that cortisol affects learning and memory, making older memories difficult to retrieve and new memories stronger. Think about a time you were feeling particularly stressed--it was probably harder to call up old memories, but it's likely the situation you were in at the time is firmly part of your memory now. This type of reaction could be particularly beneficial during exposure therapy, where the objective is to reduce the effects of older fear-based memories and form new, calmer ones.
40 patients, all with a fear of heights, were treated with three sessions of exposure therapy. The subjects received either cortisol or a placebo an hour before each exposure therapy session, and then were evaluated to see how effective the therapy was. The researchers found that those who had been treated with the cortisol had a significantly greater reduction in their fear of heights, acute anxiety during exposure to heights, and their inclination to avoid situations that might involve heights. Previous studies have found similar results with cortisol and exposure therapy for social anxiety and for fear of spiders, suggesting that cortisol has potential for assisting treatment for a variety of anxiety disorders and phobias.