We have observed an unexpected 17-fold increase in risk of fatal [corrected] myocardial infarction (relative risk 16.9, 95% confidence interval 3.9-72.8) associated with current use of psychotropic drugs. This incidental finding, in a case-control study of cardiovascular mortality in women aged 16-39 not designed to test any hypothesis about psychotropic drugs, should be treated cautiously. There is, however, evidence of a relation between psychiatric morbidity and cardiovascular disease and the association recorded here requires further investigation.