ObjectiveNoncompliance with antihypertensive treatment is a significant health concern. Researchers have suggested that the absence of definable symptoms associated with elevated blood pressure (BP) attenuates patients' motivation to use medication. The current study evaluated the relation of psychological variables, including symptoms, perceptions of BP, and perceptions of medication efficacy, to physiological variables, including actual BP and the use of active antihypertensive medication vs. placebo.MethodsParticipants included 54 mildly hypertensive men who were participating in a placebo-controlled, double-blind study of the quality-of-life effects of antihypertensive therapies. Survey data and BP measurements were obtained during a series of clinic visits.ResultsMixed-model analysis of variance was used to evaluate both between- and within-person relations of psychological to physiological state. Results revealed significant within-person associations between predicted and actual BP. Negative mood was closely related to predicted, but not actual, BP. Participants were also relatively accurate in rating active medications as more effective than placebo. Between-persons analyses did not show relations of symptoms or moods to actual BP.ConclusionsThe significant within-person relations of estimated to actual BP suggest that some individuals may be able to estimate their own BP, although the accuracy of these estimates is limited. The findings may explain patients' belief that they can self-monitor BP. The results have implications for theories of the mental representation of illness and for efforts to improve compliance with antihypertensive therapy.