Previous research has shown that a diagnosis of hypertension is associated with subsequent increases in resting blood pressure, and there is preliminary evidence of a cross-sectional association between hypertension labeling and the white coat effect. The white coat effect may be particularly problematic in prehypertensives, because a small elevation in clinic blood pressure could result in crossing the diagnostic cutoff for hypertension, potentially leading to misdiagnosis and unnecessary treatment. This study will examine effects of prehypertension labeling on clinic and ambulatory blood pressure, and will examine potential psychological mediators of these associations.