Detailed Explanation
An adverse drug reaction differs from an adverse event in that it implies a suspected causal relationship between the medicinal product and the observed harm. While adverse events encompass all untoward medical occurrences temporally associated with drug use regardless of causality, adverse drug reactions represent the subset of events where evidence supports a reasonable possibility that the product contributed to or caused the effect. This distinction has significant regulatory implications, as adverse drug reactions trigger different reporting requirements and inform the product's characterized safety profile.