Nocebo in cerebellar ataxia: A systematic review and meta-analysis of placebo-controlled clinical trials

Abstract

INTRODUCTION: Nocebo, the negative counterpart of the placebo phenomenon results in the induction of adverse events (AEs) following the administration of an inert substance. Nocebo has been demonstrated to be associated with low treatment compliance in clinical trials, thus affecting treatment outcomes. This study sought to determine the prevalence of nocebo in cerebellar ataxia. METHODS: A systematic literature search was conducted on Pubmed for randomized controlled trials (RCTs) for cerebellar ataxia treatments. The number of drug-related AEs and the number of withdrawals due to drug intolerance in the placebo group were statistically analysed. RESULTS: The literature search identified 214 studies, of which 6 studies fulfilled the inclusion criteria. Approximately 1 in 20 (4.8%) placebo-treated patients withdrew treatment due to AEs and approximately 1 in 7 (13.8%) placebo-treated participants reported at least one AE. Participants in cerebellar ataxia trials reported similar AEs across both treatment groups (active and placebo). CONCLUSION: Our results demonstrate that the nocebo effect in cerebellar ataxia is amongst the lowest in neurological diseases.