BMJ 2006;332:886-891 (15 April), doi:10.1136/bmj.38765.519850.55 (published 6 March 2006)

Research

Are some people sensitive to mobile phone signals? Within participants double blind randomised provocation study

G James Rubin, research fellow1, Gareth Hahn, senior research nurse1, Brian S Everitt, professor emeritus of biostatistics2, Anthony J Cleare, senior lecturer1, Simon Wessely, professor of epidemiological and liaison psychiatry1
1 King's College London, Institute of Psychiatry, Department of Psychological Medicine, Section of General Hospital Psychiatry, Weston Education Centre (PO62), London SE5 9RJ, 2 King's College London, Institute of Psychiatry, Department of Biostatistics and Computing, London SE5 8AF


Correspondence to: G J Rubin g.rubin@iop.kcl.ac.uk


Abstract

Objective To test whether people who report being sensitive to mobile phone signals have more symptoms when exposed to a pulsing mobile signal than when exposed to a sham signal or a non-pulsing signal.

Design Double blind, randomised, within participants provocation study.

Setting Dedicated suite of offices at King's College London, between September 2003 and June 2005.

Participants 60 "sensitive" people who reported often getting headache-like symptoms within 20 minutes of using a global system for mobile communication (GSM) mobile phone and 60 "control" participants who did not report any such symptoms.

Intervention Participants were exposed to three conditions: a 900 MHz GSM mobile phone signal, a non-pulsing carrier wave signal, and a sham condition with no signal present. Each exposure lasted for 50 minutes.

Main outcome measures The principal outcome measure was headache severity assessed with a 0-100 visual analogue scale. Other outcomes included six other subjective symptoms and participants' ability to judge whether a signal was present.

Results Headache severity increased during exposure and decreased immediately afterwards. However, no strong evidence was found of any difference between the conditions in terms of symptom severity. Nor did evidence of any differential effect of condition between the two groups exist. The proportion of sensitive participants who believed a signal was present during GSM exposure (60%) was similar to the proportion who believed one was present during sham exposure (63%).

Conclusions No evidence was found to indicate that people with self reported sensitivity to mobile phone signals are able to detect such signals or that they react to them with increased symptom severity. As sham exposure was sufficient to trigger severe symptoms in some participants, psychological factors may have an important role in causing this condition.

Trial registration ISRCTN81432775 [controlled-trials.com] .



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Rapid Responses:

Read all Rapid Responses

Too much radiation leaked during sham exposure
David Bücher
bmj.com, 13 Mar 2006 [Full text]

There is evidence that emf radiation is harmful to life. High levels are obviously harmful but with low levels such as from cell phones, the jury is still out. There was a study a number of years ago which found that cops who used hand held radar devices had a higher than average incidence of cancer.