AN INCREMENTAL MODEL TO ISOLATE SPECIFIC EFFECTS OF BEHAVIORAL TREATMENTS IN ESSENTIAL-HYPERTENSION

To prove clinical effectiveness of behavioral treatments in essential hypertension, an incremental repeated measures design was combined wit h findings that positive expectancies (placebo factors) potentiate spe cific effects. If positive expectancy effects were maximized in a Base line Control Phase (6-26 weeks of BP stabilization), specific effects might be isolated as well as potentiated in a Learning Phase (2a, 6 we eks, twice/week; 2b, 6 weeks, once/week-fading). Follow-up Phase 3 was six weeks, once/week; six months, once/month; and at 12 months. To eq ualize groups across seasons over 12 years of regular clinical work, 1 17 volunteer outpatient veterans with borderline to moderate essential hypertension (130-170190-110) were assigned in order of entry (10-20 each year) to one of four Treatments: R, simple relaxation; REMG, R EMG biofeedback; BP, BP biofeedback only; RBP, R + BP; or to an inert Control Group (TA, reading about transactional analysis without skills training). The four Treatment groups showed modest but consistent BP decreases during Phase 2 (p range from .0001 to .01). Control Phase pl acebo effects matched those in the Control Group (no BP decrease after Baseline). With a two-way mixed ANOVA design, Learning Phase 2 isolat ed specific effects of behavioral treatments, while the Control Phase 1 with liberal placebo factors potentiated specific effects during reg ular clinical work.