Applying Bradford Hill's criteria for causation to neuropsychiatry: challenges and opportunities.

Establishing an argument of causation is an important research activity with major clinical and scientific implications. Sir Austin Bradford Hill proposed criteria to establish such an argument. These criteria include the strength of the association, consistency, specificity, temporal sequence, biological gradient, biologic rationale, coherence, experimental evidence, and analogous evidence. These criteria are reviewed with the goal of facilitating an increase in rigor for establishing arguments of causation in neuropsychiatry. The challenges and opportunities related to these criteria in neuropsychiatry are reviewed, as are two important arguments for causation: one for poststroke depression and one for brain injury as a cause of psychiatric disorders.