Intensive design in evaluating anxiolytic agents. Academic Article uri icon


  • The purposes of this study were: (1) to test the usefulness of intensive design in detecting the effects of an established antianxiety agent in a single patient studied for a period as brief as 8 weeks and (2) to explore the usefulness of combining intensive and extensive designs by jointly analyzing the results from several similarly treated patients. Fifteen primarily anxious, psychoneurotic patients aged 21-50 and scoring 17 or more on the Taylor Manifest Anxiety Scale were admitted to the study; and 11 completed the full treatment program. Medications were diazepam 5 mg t.i.d. and a matching placebo, administered under double-blind conditions. Patients were treated for 8 weeks, divided into 42-week blocks. In each block, the patient received diazepam 1 week and placebo the other, with the order in each block determined at random. The patient came weekly for evaluation, including, self-ratings on the Hopkins Symptom Checklist (SCL), global status, global change; reports of occupational and social function; resting pulse; reaction time; psychiatrist's ratings on the Hamilton Anxiety Scale, global status and global change. The patient also reported daily his mood on the Profile of Mood States (POMS). Mean deviations from the general trend for post-diazepam and postplacebo scores on each criterion were compared within patients. Diazepam-placebo differences on each criterion were analyzed between patients. Criteria that clearly recorded the anti-anxiety effect of diazepam as compared to placebo included the Hamilton Anxiety Scale, the psychiatrist's global status and global change ratings, the SCL Anxiety and Somatization Scales, and the POMS Anxiety Scale. Other criteria that showed a reliable diazepam effect included SCL Depression (decrease), POMS Vigor (increase), POMS Fatigue (decrease), SCL Anger (increase), and reaction time (increase). The most sensitive criteria distinguished diazepam from placebo even when results were considered only from the first 6 patients during their first 4 weeks of treatment- a total of 24 patient weeks of treatment. The factors contributing to the sensitivity of this design were investigated and discussed.

publication date

  • March 1977