Does proof of casualty ever exist in pharmacovigilance?

Identifying the adverse effects of drugs, thus transforming adverse events into adverse drug reactions, is a useful and necessary but complicated task. Objective proof of a causal relationship between a drug and a specific event is quite exceptional. In most cases, this relationship remains subjective and is no more than inner conviction. Several means are at our disposal to achieve causal assessment: spontaneous reporting, clinical trials, cohorts with and without controls, and case-control studies, with each having advantages and limitations. The search for casualty in pharmacovigilance is a necessary scientific goal, but a high degree of suspicion may be all that is necessary to withdraw a drug from the market if it is suspected of causing serious adverse effects.