Electrical sensitivity
Electrical sensitivity (ES) - sometimes also called electrosensitivity or electromagnetic hypersensitivity (EHS) - is a condition in which a person experiences physical and/or psychological symptoms that they report to be aggravated by electric or magnetic fields (EMF) or other electromagnetic waves at exposure levels tolerated by the general public. It is a matter of controversy whether EMF exposure causes sufferers' symptoms, and the balance of evidence from provocation studies so far indicates that the link is false. There are over 30 studies into Electrical Sensitivity, of which the majority have found no causal relationship between electromagnetic fields and the symptoms being suffered. The World Health Organization state that there is no known scientific basis for such a link; but many sufferers and their support groups are firmly convinced of a causal relationship.

# Symptoms and severity
Initial reports of ES in the medical literature focused on individuals who reported symptoms following work with visual display units. However, many other electrical devices have also been reported as causing symptoms and recent surveys of ES sufferers have found that base stations for mobile and cordless phones, overhead power lines, electrical transformers and mobile phone handsets are now the most commonly cited sources of ill health.
The health effects reported by electrosensitivity sufferers tend to be various subjective symptoms which are 'non-specific': that is, which can occur in many different illnesses or diseases. As yet, no consistent evidence has been found of any objective signs of disease in this group. Initial Swedish and Nordic reports were mainly of facial skin effects attributed to extensive use of visual display units, such as dry eyes and burning skin.
However, recently in Europe as a whole and in the USA, a smaller group of people has reported more general and severe symptoms such as headache, fatigue, tinnitus and whole-body skin symptoms. A 2005 Health Protection Agency report  noted the overlap in many sufferers with other syndromes known as symptom-based conditions, FSS (Functional Somatic Syndromes) and IEI (Idiopathic Environmental Intolerance).
Figures from Levallois (2002) and Carlsson et al (2005) both show over 50% of ES sufferers also reporting Multiple chemical sensitivity or similar conditions. Other authors have noted that people reporting severe ES generally have these conditions or have had high levels of use of electrical equipment such as mobile phones. , Smith 1997(citation?): also ).
People who claim to be ES sufferers report different levels of susceptibility to electric fields, magnetic fields and various frequencies of electromagnetic waves (including fluorescent and low-energy lights, and microwaves from mobile and cordless/portable phones). .  Other surveys of ES sufferers have not been able to find any consistent pattern to these symptoms. Instead symptoms reflecting almost every part of the body have been attributed to EMF exposure.
A minority of people who report ES claim to be severely affected by it. For instance, one survey has estimated that approximately 10% of ES sufferers in Sweden are on sick leave or have taken early retirement or a disability pension, compared to 5% of the general population,  while a second survey has reported that of 3046 people who experienced 'annoyance' from electrical equipment, 340 (11%) reported 'much' annoyance.
 For those who are severely affected, ES can have a significant impact on their quality of life, causing physical, mental and social impairment and psychological distress..

# Prevalence
A questionnaire survey of 2,072 people in California found that the prevalence of claimed ES within the sample group was 3.24% (95% CI 2.83.68%), with ES being defined as "Being allergic or very sensitive to getting near electrical appliances, computers, or power lines" (response rate 58.3%). A similar questionnaire survey from the same year in Stockholm County (Sweden), found a 1.5% prevalence of ES amongst the sample group, with ES being defined as "Hypersensitivity or allergy to electric or magnetic fields" (response rate 73% 
). A more recent survey of prevalence of 'annoyance' relating to visual display units, fluorescent tube lighting and other electrical equipment among the general Swedish population reported the prevalence of 'much annoyance' relating to these devices to be 0.8%, 1.4% and 0.4% respectively.
An expert group from the European Commission also attempted to estimate the extent of ES within EU countries.  The group reported that estimates of the total number of cases differed substantially between countries as well as between the answering groups, with self aid group (SAG) estimates consistently around ten times higher than those of centres of occupational medicine (COM). Estimates ranged from less than a few cases per million of the population (COM estimates from UK, Italy and France) to a few tenths of a percent of the population (SAG estimates in Denmark, Ireland and Sweden). The group concluded that the differences in prevalence were at least partly due to the differences in available information and media attention around ES that exist in different countries. Similar views have been expressed by other commentators (, section 4.6).

# Role of electromagnetic fields in causing ES
By definition, individuals who report ES believe that EMF from common electrical devices can trigger or exacerbate their symptoms. However, as these fields tend to be much weaker than the exposure levels generally accepted to cause physiological effects, the role that EMF plays in the etiology of the condition has been the topic of much controversy: sufferers and their support groups are firmly convinced of a causal relationship with EMF's, whereas at present the scientific literature does not support such a link. Some professionals consider ES to be a real physical condition for which the cause is unclear; others consider it to be a psychosomatic illness. Some sufferers and support groups argue that the situation has become politicised to the extent that the outcomes of studies may have been influenced by the widespread implications that acceptance of such a connection would have on future policy.
A systematic review was published in 2005 which looked at the results of 31 experiments testing the role of EMF in causing ES. Each of these experiments exposed people who reported ES to genuine and sham electromagnetic fields under single- or double-blind conditions . The review concluded that "The symptoms described by 'electromagnetic hypersensitivity' sufferers can be severe and are sometimes disabling. However, it has proved difficult to show under blind conditions that exposure to EMF can trigger these symptoms. This suggests that 'electromagnetic hypersensitivity' is unrelated to the presence of EMF, although more research into this phenomenon is required." Since then, at least three further double-blind experiments have been published , each of which has suggested that people who report electrosensitivity are unable to detect the presence of EMFs and are as likely to report ill health following a fake or nocebo exposure as following exposure to genuine EMF.
Given this evidence, the World Health Organisation has concluded that "there is no scientific basis to link EHS symptoms to EMF exposure"
. Disagreement over this continues, however, as exemplified by the Freiburger Appeal: a petition originated by the German environmental medical group IGUMED stating that "we can see a clear temporal and spatial exposure between the appearance of  disease and exposure to pulsed high-frequency microwave radiation", and demanding radical restrictions on mobile phone use.

# Possible Treatment and Symptom Alleviation
As the causes, let alone existence, of electrical sensitivity are unknown, no treatment for ES exists.  It has been suggested that the symptoms have other, undiagnosed, causes, or are in fact psychological in nature ; note that the existence of the perceived symptoms is not questioned. For those that feel that they are electrically sensitive, avoidance, as far as possible, is the main strategy practised by those who claim to suffer from severe ES. However, avoidance presents major practical difficulties in modern society. Other methods often used by sufferers include screening/shielding (such as earthed/grounded metallic netting or paints), electrical filters and treatment of underlying conditions, often using complementary and alternative therapy.
A 2006 systematic review identified nine clinical trials testing different treatments for ES: four studies tested cognitive behavioural therapy, two tested visual display unit filters, one tested a device emitting 'shielding' EMF, one tested acupuncture and one tested daily intake of tablets containing vitamin C, vitamin E and selenium. The authors of the review concluded that "the evidence base concerning treatment options for ES is limited and more research is needed before any definitive clinical recommendations can be made. However, the best evidence currently available suggests that cognitive behavioural therapy is effective for patients who report being hypersensitive to weak EMFs."
A recent report by the UK Health Protection Agency concluded that ES needs to be considered in ways other than its etiology: that is, the suffering is real, even if the immediate cause is wrong, and that considering only whether EM was a causative factor was not meeting the needs of sufferers, although continued research on etiology was essential.