Dataset Information

No evidence that attentional bias towards pain-related words is associated with verbally induced nocebo hyperalgesia: a dot-probe study.

ABSTRACT:

Introduction

Placebo and nocebo effects in pain are well documented. One leading explanation is that instructions indicating that pain will either increase or decrease after receipt of a treatment give rise to expectations for increased or decreased pain. However, the psychological mechanisms through which expectations affect pain perception are not well understood. One possibility is that the expectation of increased pain leads to anticipatory anxiety, which in turn increases attention towards painful sensations.

Objectives

The aim of this study was to test the hypothesis that attention mediates nocebo hyperalgesia. This was done by measuring attentional bias towards pain using a dot-probe task both before and after a nocebo manipulation.

Methods

Ninety-six healthy volunteers were randomized to receive one of the following: (1) an inert nasal spray with placebo instructions, (2) an inert nasal spray with nocebo instructions, or (3) no treatment. Participants completed measures of expectations, anxiety, and attention bias (dot-probe paradigm) both before and after randomization.

Results

Results showed that the nocebo instructions induced expectations for increased pain and resulted in nocebo hyperalgesia. Conversely, the placebo instruction failed to induce expectations for decreases in pain and did not demonstrate any placebo analgesia. Furthermore, despite the significant expectancies for pain and subsequent nocebo hyperalgesia, there were no differences between the nocebo group and either the placebo or no-treatment group for anxiety or attentional bias.

Conclusion

The results are consistent with the expectancy model of placebo and nocebo effects. That is, changes in expectations seemed to be necessary to induce a placebo or nocebo effect. However, there was no evidence that anxiety or attention bias towards pain-related stimuli was necessary to achieve nocebo hyperalgesia.

SUBMITTER: Coleshill MJ

PROVIDER: S-EPMC8108596 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundThe aim of this study was to improve our understanding of the underlying mechanisms in the maintenance of depression. We examined attentional bias (AB) for negative and positive adjectives and general threat words in strictly-defined clinical groups of participants with pure Major Depressive Disorder (MDD) without a history of anxiety disorders (AD), mixed MDD and AD, and remitted participants.MethodWe investigated both stimulus specificity and time course of AB in these groups, adopting a cross-sectional design. Data were drawn from the large scale Netherlands Study of Depression and Anxiety (NESDA), from which we selected all participants with pure current MDD without a history of AD (n = 29), all participants with current MDD and co-morbid AD(s) (n = 86), all remitted MDD participants (n = 294), and a comparison group without (a history of) MDD or ADs (n = 474). AB was measured with an Exogenous Cueing Task covering short and long presentation times (500 and 1250 ms) and 4 stimulus types (negative, positive, threat, neutral).ResultsBoth traditional and trial level (dynamic) AB scores failed to show an AB for negative adjectives in participants with MDD or mixed MDD/AD. Specifically for long duration trials (1250 ms), remitted participants showed a larger AB traditional score (albeit the actual score still being negative) than the comparison group. The mixed MDD/AD group showed a higher trial-level AB score away from positive adjectives (1250 ms) than the comparisons. In addition, the mixed MDD/AD group showed higher and more variable trial-level AB scores away from short and towards longer presented general threat words together with a non-significant tendency to show less negative traditional AB scores for threat trials (500 ms) than the comparison group.ConclusionsAll in all, the findings do not corroborate the view that an AB towards negative or away from positive adjectives is critically involved in currently depressed individuals. Yet, the relatively high (less negative) AB score for negative adjectives in remitted individuals points to the possibility that an AB for negative information may be involved as a risk factor in the recurrence of MDD.