Does Mobile Phone Radiation Cause Symptoms?

A perceived relationship between electromagnetic radiation (EMR) exposure, such as is associated with mobile phone technology and electromagnetic hypersensitivity syndrome (EHS)^1,2 has been established and accepted by many credible organisations.^3,4 Indeed, the weight of evidence has proved enough for court cases to be won by people claiming damages and/or support over the emergence of EHS-related symptoms.⁵

However, while the evidence may be good enough for the government and the courts, is it good enough for science? In fact, it remains completely unclear whether EMR exposure precedes the development of EHS symptoms, or whether psychological issues are at play. This lack of data remains a source of an impasse in a debate critical to our societies as they develop into the digital age.

Many overviews of the available science suggest that there are no existent studies allowing a causal relationship between EMR exposure and EHS emergence to be corroborated or disproved^6,7. Most studies examining the relationship between EMR exposure and reports of physical and psychological symptoms have been correlational^1,8,9.

These studies often use naturally occurring situations, such as proximity to base stations or mobile phone usage, and examine symptoms recorded in volunteer participants. A problem with such an approach is that, no matter how well controlled these studies are (and some are very well conducted), they will never give the causal evidence needed to determine whether EMR exposure, itself, produces EHS.

Any correlations that are noted between EMR exposure and symptoms could imply any number of causal associations between the two. Of particular importance in this regard has been the suggestion of the "nocebo" effect¹⁰; that is, symptoms are attributed to EMR, but are not actually caused by such environmental radiation¹¹. It is possible that EMR is identified as a cause of symptoms by individuals who cannot identify any other reason for these presenting symptoms, and who are concerned about EMR exposure⁶. This possibility is at the root of many people taking EHS less seriously than many others would prefer.

Clearly, an answer to this question requires an experiment—but this definitive experiment, sadly, has not been forthcoming. A number of experiments have attempted to explore the EMR-EHS relationship, and these studies are classed as "sensitivity" or "provocation" tests.

In these studies, individuals experience either EMR exposure or sham exposure, and the impacts of the two conditions on the individuals are noted—in terms of whether they can sense the EMR ("sensitivity"), or experience problems because of it ("provocation")^12,13. Unfortunately, for a variety of reasons, these studies have not provided the necessary evidence to allow answers to the key question about causality.

Differential subjective-perception thresholds for detecting the presence of EMR have been observed in those with and without EHS. These results suggest greater sensitivity to EMR in those claiming EHS^14,15, but it is unclear whether any symptoms accompanied the ability to discriminate the presence of EMR. One study has demonstrated symptom emergence in a provocation test, albeit with a small sample of 10 individuals, in a non-blinded study¹⁶. However, this positive result contrasts with negative findings reported in other studies¹⁷, and this pattern of contrasting results has been noted in a number of reviews^6,7,10.

Several methodological problems in these sensitivity and provocation tests have been noted, which reduce the weight of their conclusions. These methodological issues include initial participant sampling problems, as it is not certain that the participants had credible claims of EHS. Mainly, this is due to a reliance on self-report of EHS from the participants, instead of a thorough examination and consideration of the participants’ problems.

An over-narrow selection of outcome measures may have seriously biased the results of these studies. There are also poor control conditions, including a lack of randomization between sham and EMR exposure, and a lack of double-blinding of participants and experimenters. Weak statistical power in many of the experiments means that some of the studies that failed to show a statistically reliable difference between EMR and sham exposure sometimes did so because of participant withdrawal—making a study less than definitive.

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Problematically, the symptomatic correlates of EMR exposure are highly similar to those presented by individuals who report other physical and psychological problems, such as Myalgic Encephalomyelitis¹⁸, other environmentally-related disorders¹⁹, and even digital-dependency²⁰. Moreover, there are data suggesting a relationship between EHS and hyperchondraisis²¹—which is an area of some controversy. Some have claimed that around 50 percent of putative EHS cases may result from the presence of co-morbid or primary psychiatric problems¹⁹; although it should be noted that, for general environmental sensitivities, up to 40 percent of cases have plausible environmental causes²².

Furthermore, the personalities, social situations, and co-morbid symptoms, of those who report EHS may themselves influence the nature and severity of the reported symptoms²³. All of this makes an assessment of the precise nature and actual cause of EHS particularly difficult to establish and allows easy dismissal of EHS as being causally-related to EMR, or even as existing in its own right.

While it is vital to develop appropriate studies to address this issue, it should be remembered that there are a number of biological mechanisms explaining why non-ionizing EMR may produce EHS symptoms². The existence of credible biological routes that would convert exposure to EMR into EHS symptoms has to keep this issue on the scientific agenda.

For example, non-ionizing EMR activates voltage-gated calcium channels, which occur in high densities across the nervous system, and are associated with a wide range of neuropsychiatric effects²⁴. Alternatively, EMR is known to produce tissue inflammation, mediated by histamine release; and inflammation-related hyper-histaminemia, oxidative stress, autoimmune response, capsulothalamic hypoperfusion, and a deficit in melatonin metabolic availability are markers of this process²⁵. Again, although both hypotheses are plausible, they cannot be resolved until research evidence is gained.

It is clear that the nature of EHS, and any causal linkage between EMR and EHS, need establishing simultaneously in an experimental context, conducted on a large, well-investigated sample. These data are critically missing from the current scientific literature. Until such a study is conducted, we are in a position where it cannot unequivocally be concluded that EMR has caused harm to individuals, nor can the calls for the increased rollout of the EMR-based technology that supports the digital world be deemed safe or sensible.

Politicians attempt to gain support by championing the use of such technology (because the mobile technology it supports is popular), claiming that it will increase efficiency and save money²⁶; but, scientifically, they cannot discount the possibility that it may do just the opposite, due to the harm it could cause to certain groups of people with sensitivity to this form of radiation.