Antidepressant Drugs and the Risk of Intracranial Bleeding: Parsing an Observational Study

Observational studies have suggested that antidepressant drug use is associated with a small but increased risk of intracranial bleeding. Because of the widespread use of antidepressant drugs and the potential public health significance of this finding, the current article critically evaluates the methodology and findings of a recently published observational study. Observational studies reveal associations, but cannot establish causality. Establishing causality from observed associations requires evidence from different scientific perspectives. Claims arising from observational studies are likely to be wrong, especially for small effects, because of bias and confounding. Statistical testing does not prove the validity of an association, nor does a meta-analysis of multiple observational studies. A valid association may not be clinically meaningful if the magnitude of the effect is small or the outcome is rare. Based on a critical analysis of these observational studies, it is concluded that the risk of intracranial bleeding associated with antidepressant drugs is likely to be a false alarm. [Journal of Psychosocial Nursing and Mental Health Services, 54(2), 21-24.].