Making the decision to stop pain: Probability and magnitude effects of expected pain relief on the choice of analgesics


  • C. Lin

    Corresponding author
    • Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, Nuffield Division Anaesthetics, University of Oxford, John Radcliffe Hospital, Oxford, UK
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  • Funding sources

    Chia-shu Lin is sponsored by the Overseas Research Student Awards Scheme (ORSAS) from the UK Secretary of State for Education and Science.

  • Conflicts of interest

    None declared.


Chia-shu Lin




Pain is a major ailment that motivates individuals to look for treatment. Despite its enormous clinical relevance, very little is known about the factors that influence our preference of an analgesic (or pain-relieving treatment). The current study investigated the influence of the information regarding the probability and the magnitude of the expected analgesic effect on preference of analgesic options.


Twenty-four healthy volunteers were instructed to imagine pain across different scenarios and choose between two hypothetical analgesics that differed in their probabilities to successfully relieve pain and the magnitude of their expected analgesic effects. The conservative analgesic was more reliable but less potent than the radical analgesic, whereas the radical analgesic was less reliable but more potent than the conservative analgesic.


Consistent with the predictions of prospect theory, a larger proportion of the participants chose the radical analgesic when the overall probability of both analgesics decreased, and when the potency of the radical analgesic was expected to be stronger relative to the conservative analgesic. At the individual level, individuals' relative imagined pain relief (radical analgesic/conservative analgesic) predicted their preference for the radical analgesic.


Our findings revealed that preference of analgesic options is mediated by the overall probability of analgesic effect and the relative potency of analgesics. The expected relief one imagines to obtain from analgesics would guide preference. The findings highlight the importance for clinicians to understand how patients subjectively frame the probability and magnitude factors related to decision making in medical context.