Acetaminophen enhances the reflective learning process.

Rahel Pearson,Bethany Hamilton,Charles S Carver,Seth Koslov,Jason Shumake,Christopher G Beevers

doi:10.1093/scan/nsy074

Rahel Pearson, Bethany Hamilton + Show 4 more

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https://doi.org/10.1093/scan/nsy074

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Abstract

Acetaminophen has been shown to influence cognitive and affective behavior possibly via alterations in serotonin function. This study builds upon this previous work by examining the relationship between acetaminophen and dual-learning systems, comprising reflective (rule-based) and reflexive (information-integration) processing. In a double-blind, placebo-controlled study, a sample of community-recruited adults (N = 87) were randomly administered acetaminophen (1000 mg) or placebo and then completed reflective-optimal and reflexive-optimal category learning tasks. For the reflective-optimal category learning task, acetaminophen compared to placebo was associated with enhanced accuracy prior to the first rule switch (but not overall accuracy), with needing fewer trials to reach criterion and with a faster learning rate. Acetaminophen modestly attenuated performance on the reflexive-optimal category learning task compared to placebo. These findings indirectly support two positions that have been proposed elsewhere. First, they are consistent with the view that acetaminophen has an influence on the serotonergic system. Second, the findings are consistent with a proposed link between elevated serotonin function and relative dominance of effortful, rule-based processing.

Highlights

Acetaminophen is the active ingredient in many over-thecounter pain relief medications, which are taken by more than 50 million people weekly (Kaufman et al, 2002)
We predicted a significant interaction between experimental group and task condition, where those in the acetaminophen group would have enhanced performance in the reflective condition and poorer performance in the reflective condition
This study examined whether acetaminophen altered participants’ performance on reflective-optimal and reflexive-optimal category learning tasks

Summary

Introduction

Acetaminophen is the active ingredient in many over-thecounter pain relief medications, which are taken by more than 50 million people weekly (Kaufman et al, 2002). A down regulation of serotonin receptors has been observed in the brains of rodents who were administered acetaminophen, suggesting increases in central serotonin (Pini et al, 1996; Srikiatkhachorn et al, 2000). This aligns with other evidence of increased availability of serotonin following acetaminophen administration (Pini et al, 1996; Courade et al, 2001). Perhaps as a consequence of these increases in central serotonin, acetaminophen intake has been shown to increase the number of serotonin transporter binding sites, suggesting enhanced serotonin reuptake (Srikiatkhachorn et al, 2000)

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