Background: Poor adherence is estimated to cause 125 thousand deaths per year and is linked to 10% of all hospital stays in the U.S. Up to one third of elderly hypertensive patients don’t have adherence, which is responsible for high proportion of hospitalizations. Hypertension is also related to poor performance in tests that assess cognitive functions. On the other hand, poor cognitive performance is associated with low adherence to treatment. Objective: To assess the association between cognitive function, anxiety and psychiatric disorders with adherence to drug treatment in patients with hypertension. Methodology and Principal Findings: This a cohort studies with 56 adult patients with uncontrolled hypertension who participated of all meetings of a pharmaceutical intervention in a randomized clinical trial of pharmaceutical care. Cognitive function was measured by the Mini Mental State Examination (Mini-mental). The memory was measured by digit and word spans, tower and church shadow test, short story test and metamemory. Anxiety and psychiatric disorders were evaluated by the State Trace Anxiety Inventory and the Self-Report Questionnaire, respectively. The participants were classified as adherent or non-adherent to the drug treatment, according to the identification of plasma levels of hydrochlorothiazide. All non-adherent patients (n = 12) and 35 out 44 (79.5%) patients with adherence to treatment had at least one memory test with an altered score (P = 0.180). Participants with an unsatisfactory score in the Mini-mental had six-fold higher risk of non-adherence to treatment when compared to those with a normal score (RR = 5.8; CI 95%: 1.6– 20.8; P = 0.007). The scores of anxiety and psychiatric disorders were not associated with adherence to the pharmacological treatment. Conclusion: Cognitive deficit impairs adherence to drug therapy and should be screened as part of a program of pharmaceutical care to improve adherence to treatment
