A significant unmet medical need exists for analgesics having better efficacy/tolerability than those currently available. The development of such drugs relies heavily on preclinical animal models of pain that typically involve the delivery of a presumably painful stimulus and measurement of a pain-evoked behavior (e.g. withdrawal responses). Candidate analgesics are tested for their ability to decrease pain-evoked behaviors. There are two general limitations to a reliance on these types of behavior. First, pain is associated not only with an increase in some categories of behaviors, but also with decreases in other categories of normally adaptive behaviors (e.g., feeding, locomotion). Consequently, an exclusive focus on pain-evoked behavior may neglect important consequences of pain. Indeed, patients with chronic pain often report spontaneous pain, which by definition does not involve a response to external stimulation and which cannot be assessed using standard stimulus-response approaches. A second limitation to reliance on pain-evoked behaviors to study candidate analgesics is that drugs may decrease pain-evoked behaviors by producing motor effects that impair the animal's ability to emit the pain-associated behavior. This necessitates the use of additional behavioral assays to measure drug effects on motor behavior. In view of these limitations, new behavioral procedures are being developed for the preclinical assessment of pain and analgesia. The symposium will feature presentations from academic and industry scientists and clinicians who are developing alternative and complementary behavioral paradigms for assessing analgesic efficacy. The speakers will also highlight how these models can be combined with existing procedures to provide a more comprehensive assessment of the impact of pain and analgesia on the organism. The symposium will conclude with a presentation on how basic scientists and clinicians can work together to develop better assessments of analgesic efficacy and to highlight novel strategies for assessing efficacy in humans.

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