The objective of this study was to explore the relationship between psychological characteristics and responses to antihypertensive drug therapy. Twenty-two hypertensive subjects underwent psychological evaluation and treatment with 1) a diuretic, hydrochlorothiazide (HCTZ); 2) an angiotensin-converting enzyme (ACE) inhibitor, quinapril; and 3) combined α+β blockade (doxazosin + betaxolol). Anger-Out scores on the State-Trait Anger Expression Inventory were positively correlated with the HCTZ-induced fall in systolic blood pressure (p<0.01); Anger-In was negatively correlated with the quinapril-induced fall in systolic pressure (p<0.05). The target systolic blood pressure (130 mm Hg) was achieved with either HCTZ or quinapril in 79% of subjects without, vs. 25% of subjects with, childhood trauma (p=0.03). Responses to doxazosin + betaxolol were not correlated with psychological characteristics. The authors conclude that both inhibited anger expression and childhood trauma are associated with reduced response to a diuretic or ACE inhibitor. Combined α/β blockade may be preferable to an ACE inhibitor or diuretic in treating selected hypertensive patients. Further studies should include examination of psychological factors in terms of the response to combined ACE inhibitor + diuretic therapy.