Failure of psychological interventions to lower blood pressure: a randomized controlled trial

BACKGROUND Previous studies have suggested that psychological interventions may be effective in reducing blood pressure. Using rigorous methodology and 24-hour monitoring of ambulatory blood pressure, we compared 2 psychological interventions with treatment using a first-line antihypertensive drug in terms of their efficacy in lowering blood pressure in patients with mild primary hypertension. METHODS In this prospective, open-label randomized controlled trial (RCT), 65 adult patients with mild, uncomplicated hypertension were randomly assigned to receive one of the following interventions for 12 weeks: (1) pharmacotherapy with hydrochlorothiazide 12.5 titrated to 25 mg/d ; (2) individualized behavioural psychotherapy, consisting of ten 1-hour sessions of stress reduction training with a psychologist; or (3) self-help psychotherapy, consisting of a 1.5-hour session with a psychologist and then daily sessions that involved reading a self-help manual and listening to an audiotape. The primary outcome measure was mean change in ambulatory blood pressure from baseline to week 12. Resting blood pressure readings were taken in the clinic, and adverse events were recorded. RESULTS Monitoring of ambulatory blood pressure over 24 hours showed that hydrochlorothiazide therapy significantly reduced both systolic and diastolic blood pressure relative to baseline, and that this reduction was significantly greater than that achieved with either individualized behavioural psychotherapy or self-help psychotherapy (mean reduction [standard error; SE] -11.03 [2.53] / -6.06 [1.56] mm Hg v. -0.08 [2.38] / 0.29 [1.47] mm Hg v. -1.23 [2.83] / -0.71 [1.75] mm Hg, respectively; p = 0.01). Neither form of psychological therapy significantly lowered 24-hour ambulatory blood pressure relative to baseline. CONCLUSION For patients with primary elevated blood pressure, 2 psychological interventions did not lower 24-hour ambulatory blood pressure, whereas hydrochlorothiazide reduced blood pressure, as expected. The findings of this RCT represent an important addition to the evidence for health care practitioners and for patients seeking psychological interventions to reduce blood pressure.