The methodological and clinical aspects of the placebo effect in angina pectoris

The study was carried out in 45 patients (36 males and 9 females) experiencing more attacks on the evaluation of an antianginal drug in a placebo-controlled trial, and to define some conditions of placebo sensitiveness in patients with angina pectoris. The study was carried out in 45 patients (36 males and 9 females) experiencing more than 5 anginal attacks a week. The drug compared with the placebo was Iso-Mack-Retard 20 believed to have a good antianginal profile. The efficacy of both the drug and placebo was assessed mainly by the number of anginal attacks per week. The differences in the efficacy between the drug and its placebo in the group studied as a whole were not statistically significant but, after exclusion of 15 placebo-sensitive patients (placebo responders), these differences increased to become statistically significant (p less than 0.01). Moreover, the study proved that the extent of the placebo effect in a population is inversely dependent on the level of neuroticism measured by Eysenck Personality Inventory, and directly dependent on the number of anginal attacks in the period before administration of the drug.