Table 3.

Domains of opioid human abuse liability laboratory testing and some recommended endpoints to assess those domains

Domain	Endpoints
Subjective effects (Primary endpoint)	Liking Likelihood to take again Drug identification Drug high
Physiological responses (Secondary endpoint)	Pupillary constriction (miosis) Respiration rate and oxygen saturation
Drug self-administration behavior (Optional endpoint)	Discrete trial choice: drug vs. drug Nonverbal operant procedure: modified progressive ratio schedule
Cognitive and psychomotor performance (Optional endpoint)	No specific recommendations at this time