Subjects with a fear of flying treated with placebo demonstrate long term improvement

Research by the Stanford University School of Medicine demonstrated that anti-anxiety medication actually makes someone with a fear of flying more sensitive to flying (more likely to panic if not sufficiently medicated), and blocks de-sensitisation, making it less likely for an individual to become accustomed to flying. 

The subjects of the research made two flights - the first where half the trial sample were given an anti anxiety pill (alprazolam - with side effects ranging from dizziness to hallucinations and aggression) the other half being given a placebo. On the second flight no medication was given. On the first flight 43% of the placebo group experienced some panic symptoms whereas the subjects who received the active medication did much better with only a few demonstrating displaying panic symptoms. Interestingly, on the second flight (where no medication was administered) only 29% of the placebo group experienced panic, from the group who received the active medication on the first flight 71% experienced panic. The placebo group experienced a significant de-sensitisation to their phobia.

FH Wilhelm, WT Roth - Stanford University - Acute and delayed effects of alprazolam on flight phobics during exposure