Effects of concurrent diazepam treatment on the outcome of exposure therapy in agoraphobia

In a study designed to evaluate the impact of benzodiazepine use on the outcome of behaviour therapy, 91, severe, chronic agoraphobics (46 BDZ users and 45 non-users) were randomly allocated on a double-blind basis to in vivo exposure with low-dose diazepam (ED) or placebo (EP). Drug doses were adjusted on the basis of weekly psychiatric assessments over weeks 1-4. Patients had 8 x 2 hr exposure sessions (weeks 5-12) and were then withdrawn from medication (weeks 13-16). Re-assessments were completed at weeks 4, 12 and 16, and follow-up assessments at approx 20, 46 and 72 weeks. In the analysis of the results, the clinical outcome was evaluated in relation to the therapeutic regime (ED vs EP) and prior BDZ use (users vs non-users). The results showed that the ED group had greater changes in anxiety than the EP group during the drug manipulation phases (anxiety increasing during BDZ withdrawal). There were no group differences in agoraphobic symptoms and no evidence that the outcome of the behavior therapy was significantly affected by concurrent BDZ treatment. There were significant improvements in agoraphobic symptoms over the treatment period, with no evidence for relapse of treatment gains on withdrawal from BDZ, nor for differential responses over the one year follow-up. Initial differences between users and non-users were less marked than expected, although there was a trend for more drop-outs among users across both ED and EP groups.