Assessing the reliability and association of pain ratings and skin conductance responses: Insights from habituation and sensitization to pain

Repeated painful stimulation results in substantial inter-individual differences in habituation and sensitization. The extent to which these responses reflect state versus trait characteristics remains unclear, highlighting the need to assess the reliability of these differences over time. Furthermore, the association between subjective pain ratings and skin conductance responses (SCR) has not been examined in this context. This preregistered study investigated profiles of habituation and sensitization to pain across two sessions using pain ratings and SCR. Participants underwent repeated painful electrical stimulation over two sessions separated by four weeks, receiving 75 stimuli across three runs per session. Pain intensity was rated after each stimulus, and continuous SCRs were recorded. Our results demonstrated moderate test-retest reliability of both pain ratings and SCRs, with within-run measures showing greater consistency than across-run measures. Remarkably, participants displaying sensitization exhibited higher reliability than those with habituation or no-change patterns. High test-retest reliability could suggest a trait-like response with reduced adaptability to repeated stimulation, while a higher variability (and thus low test-retest reliability) indicates state-dependent flexibility and adaptability. Our results suggest that interventions to modulate pain could be targeted at changing such sensitization patterns and promoting habituation. Furthermore, pain ratings showed diverse trajectories of habituation and sensitization, whereas SCRs predominantly habituated. This dissociation between subjective pain perception and autonomic responses challenges the prevailing view that higher pain ratings correspond to elevated SCRs. Together, these results underscore the importance of considering habituation and sensitization dynamics, with subjective and physiological measures providing complementary insights into the multidimensional pain response. Perspective: Repeated painful stimulation resulted in patterns of habituation and sensitization, with large individual variability. Test-retest reliability was moderate, with higher consistency for individuals who sensitize. A dissociation between ratings and SCR was demonstrated, with diverse response patterns of ratings and mostly habituation of the SCR.