Case—Control Studies of Cardiovascular Medications as Risk Factors for Clinically Diagnosed Depressive Disorders in a Hospitalized Population

OBJECTIVE: Certain medications used in cardiovascular therapeutics may contribute to the etiology of substance-induced mood disorders. These medications include digoxin, angiotensin converting enzyme (ACE) inhibitors, beta-blockers, and calcium channel blockers. The objective of this study was to evaluate associations between these drugs and clinical diagnoses of depressive disorders in a population of hospitalized patients. METHOD: Two case-control studies were conducted. For each study, subjects were selected from a health records data base maintained at the Calgary General Hospital. Selection of subjects in the first study was restricted to those receiving a discharge diagnosis of congestive heart failure and in the second study to subjects receiving a discharge diagnosis of hypertension. In each of these 2 studies, a single case group was selected along with 2 control groups: a psychiatric control group consisting of subjects receiving a psychiatric diagnosis other than a depressive disorder and a nonpsychiatric control group receiving no psychiatric diagnoses. Drug exposures and other variables were recorded from a chart review. RESULTS: Exposures to digoxin, beta-blockers, and calcium channel blockers were not associated with depressive diagnoses. An association was observed, however, for ACE inhibitors. An elevated odds ratio (OR) was observed in each case-control study and was stronger in female subjects and subjects over the age of 65. CONCLUSIONS: This is the first reported epidemiological evidence of an association between ACE inhibitors and depressive disorders. The design of this study does not permit a determination of whether the observed association was causal. Additional studies are needed.