USE OF CALCIUM-CHANNEL BLOCKERS AND RISK OF SUICIDE - ECOLOGICAL FINDINGS CONFIRMED IN POPULATION-BASED COHORT STUDY

Objective: To investigate possible associations between use of cardiov ascular drugs and suicide. Design: Cross sectional ecological study ba sed on rates of use of eight cardiovascular drug groups by outpatients . A population based cohort study including users of drugs to control hypertension. Subjects: The ecological study included 152 of Sweden's 284 municipalities, The cohort study included all inhabitants of one S wedish municipality who during 1988 or 1989 had purchased cardiovascul ar agents from pharmacies within the municipality. Six hundred and sev enteen subjects (18.2%) were classified as users of calcium channel bl ockers and 2780 (81.8%) as non-users. Main outcome measures: Partial c orrelations (least squares method) between rates of use of cardiovascu lar drugs and age standardised mortality from suicide in Swedish munic ipalities. Hazard ratios for risk of suicide with adjustments for diff erence in age and sex in users of calcium channel blockers compared wi th users of other hypertensive drugs. Results: Among the Swedish munic ipalities the use of each cardiovascular drug group except angiotensin converting enzyme inhibitors correlated significantly and positively with suicide rates, After adjustment for the use of other cardiovascul ar drug groups, as a substitute for the prevalence of cardiovascular m orbidity, only the correlation with calcium channel blockers remained significant (r = 0.29, P < 0.001). In the cohort study, five users and four non-users of calcium channel blockers committed suicide during t he follow up until the end of 1994. The absolute risk associated with use of calcium channel blockers was 1.1 suicides per 1000 person years . The relative risk, adjusted for differences in age and sex, among us ers versus non-users was 5.4 (95% confidence interval 1.4 to 20.5). Co nclusions: Use of calcium channel blockers may increase the risk of su icide.