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Open Access Highly Accessed Research article

Homeopathy for mental fatigue: lessons from a randomized, triple blind, placebo-controlled cross-over clinical trial

Michael Emmans Dean1, Raj Karsandas1, J Martin Bland1, Debbie Gooch2 and Hugh MacPherson1*

Author affiliations

1 Dept. of Health Sciences, University of York, York YO10 5DD, UK

2 Dept. of Psychology, University of York, York YO10 5DD, UK

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Citation and License

BMC Complementary and Alternative Medicine 2012, 12:167  doi:10.1186/1472-6882-12-167

Published: 1 October 2012

Abstract

Background

Difficulty in controlling attention can lead to mental fatigue in the healthy population. We identified one trial reporting a benefit in patients’ attention using a homeopathic formula preparation. One component of the preparation was potassium phosphate, widely available off the shelf as Kali phos 6x for cognitive problems. The aim of this exploratory trial was to assess the effectiveness of Kali phos 6x for attention problems associated with mental fatigue.

Methods

We recruited student and staff volunteers (University of York) with self-reported mental fatigue, excluding any using homeopathy or prescribed stimulants, or with a diagnosis of chronic fatigue syndrome. In a triple blind, cross-over, placebo-controlled clinical trial, 86 volunteers were randomized to receive Kali phos 6x or identical placebo 10 minutes before taking a psychological test of attention (Stroop Colour-Word Test). One week later they were crossed over and took the other preparation before repeating the test.

Results

We found no evidence of a treatment effect in a comparison of Kali phos 6x with placebo (Kali phos minus placebo = −1.1 (95% CI −3.0 to 0.9, P = 0.3) Stroop score units, Cohen effect size = −0.17) even when allowing for a weak period effect with accuracy scores in the second period being higher than those in the first (P = 0.05). We observed a ceiling effect in the Stroop test which undermined our ability to interpret this result.

Conclusions

Kali phos 6x was not found to be effective in reducing mental fatigue. A ceiling effect in our primary outcome measure meant that we could not rule out a type II error. Thorough piloting of an adequate outcome measure could have led to an unequivocal result.

Current Controlled Trials

ISRCTN16521161

Keywords:
Crossover study design; Mental fatigue; Kali phos 6x; Stroop test