Assessing abuse liability during drug development: changing standards and expectations.

As public health concerns have changed, regulatory expectations for assessing abuse liability of new central nervous system (CNS) drugs have increased. All CNS-active drugs with any properties indicating stimulant, depressant, hallucinogenic, or mood-elevating effects will require an evaluation of abuse liability. Abuse liability assessment involves the collection, analysis, and interpretation of data on chemistry and tampering, animal behavioral pharmacology, clinical trial adverse events (AEs), diversion and overdose, and potentially reinforcing (subjective) effects in recreational drug users.