Jury Still Out on CES for Depression, Anxiety, Pain, Insomnia

Batya Swift Yasgur, MA, LSW

February 13, 2018

There is sparse evidence supporting the efficacy of cranial electric stimulation (CES) for the treatment of chronic pain, depression, anxiety, and insomnia, new research shows.

In a systematic review, investigators examined the potential benefits of CES for treating chronic pain conditions, depression, anxiety, and insomnia in adults. The review showed there was "limited evidence" of the utility of CES for anxiety and depression and even less evidence to support its use in the treatment of chronic pain and insomnia.

"I think the take-home message is that the jury is still out on the effectiveness of this therapy," study investigator Paul G. Shekelle, MD, MPH, PhD, chief of general internal medicine, Veterans Affairs West Los Angeles Medical Center, California, and professor of medicine, Univeristy of California, Los Angeles, School of Medicine, told Medscape Medical News.

"It's probably safe, so it's probably not doing any harm, but I wouldn't want patients to rely only on this without first trying other treatments with a stronger evidence base for their condition, such as depression, anxiety, etc," he said.

The study was published online February 12 in the Annals of Internal Medicine.

DIY Brain Stimulation

CES is "among a growing number of noninvasive brain stimulation interventions that change brain function and have been used to treat diseases like depression and anxiety," the authors write.

In an early meta-analysis of CES for anxiety, brain dysfunction, headache, and insomnia, pooled effects for anxiety were "statistically significant, favoring treatment." No benefit was found for insomnia or brain dysfunction, and only a "small beneficial effect" was found for headache.

Currently in the United States, CES devices are available only by prescription, although they can be obtained online by consumers.

Some countries other than the United States allow consumers to purchase these devices directly from the manufacturers. As a result, physicians may receive requests for these devices, or their patients may already be using them.

"Because of this availability and the expanding interest in alternative therapies, we did this systematic review of CES for treating chronic painful conditions, depression, anxiety, and insomnia," the authors report.

"The VA [US Department of Veterans Affairs] is interested in nontraditional healthcare treatment options that improves veterans' health and well-being," said Shekelle.

"CES is one such treatment option that has been getting increasing attention, and CES has been provided by some benefit for certain patients."

He noted that the "opioid crisis and the potential use of CES as a treatment for chronic pain" are reasons for the growing interest in this alternative.

"Therefore, the VA administration asked our group for a thorough review of the evidence of effectiveness of CES for a number of high-priority conditions at VA," he said.

To investigate, the researchers searched several databases from inception to October 10, 2017, to find randomized controlled trials (RCTs) in any language of CES vs usual care or sham CES for the treatment of pain, depression, anxiety, or sleep disorders.

They also searched ClinicalTrials.gov and the websites of two manufacturers, as well as references cited by included studies, prior systematic reviews, a review by the US Food and Drug Administration, and references noted by the manufacturers.

They identified 28 articles from 26 RCTs that met eligibility criteria, but found that there were too few studies in any category of condition or of treatment with CES devices to support a meta-analysis.

The researchers regarded pooling across CES devices "to be inappropriate because different waveforms and current intensities are believed to produce different effects."

Low-Strength Evidence

The selected trials enrolled patients with painful conditions (n = 14), depression (n= 3), depression and anxiety (n = 5), insomnia, (n = 2), anxiety and insomnia (n = 1), and anxiety (n = 1).

The CES devices used in the trials included the Fisher Wallace Stimulator, an Alpha-Stim unit, the Pain Suppressor (Pain Suppression Labs), the Neurotone 101, the Electrosone-50, the Transcranial ElectroStimulator (Pulse Mazor Instruments), the Electrodorm 1, and a custom-built device.

Most trials (n = 21) were small and enrolled fewer than 30 participants per group. Twenty-one trials were conducted with active CES and a comparator variously described as "sham,""placebo," or "control. Two trials compared CES with a sham or placebo and with usual care.

Three trials compared active CES with sham or placebo and included a third group that consisted of CES of different forms (symmetrical vs asymmetrical waveform, central vs peripheral electrical stimulation, or "perceived" vs "subliminal" electrical stimulation).

All but one of the studies were described as "double-blind," although none assessed the credibility of the sham intervention, and therefore all were judged to carry a high risk for bias.

The two trials that compared CES with usual care were small, and neither trial reported a statistically significant benefit in pain outcomes for patients with fibromyalgia or a reduction in anxiety for patients with anxiety.

The trials with sham or placebo controls in patients with chronic pain conditions (eg, headache, neuromuscular pain, or musculoskeletal pain [n = 14]) yielded conflicting results.

Four trials that were conducted more than 40 years ago and one trial that was conducted in 2014 provided "low-strength evidence of a possible modest benefit," compared with sham treatments, for patients with anxiety and depression.

In all of the trials in patients with insomnia, depression, or insomnia plus depression, results were inconclusive or conflicting.

The researchers found "low-strength evidence" that CES is not associated with serious side effects.

"I think the tone of the reporting of our work should not be that 'CES doesn't work,' because that's not what the evidence shows," said Shekelle.

Rather, "the tone is, 'we don't know whether it works or not,' and better research is needed it order to determine if it does work, and for what conditions, because if it does work, it is probably safe and, relatively speaking, inexpensive," he said.

Disappointing Findings

Commenting on the study for Medscape Medical News, Wayne Jonas, MD, clinical professor of family medicine, Georgetown University, and executive director of Samueli Integrative Health Programs, who was not involved with the study, called the findings "a disappointment."

"We are looking for nondrug approaches for pain and hoped that CES would be one of them," he said.

However, CES does not seem to be harmful "if used properly, under supervision of health professionals, and not used instead of proven therapies, which is a good thing," observed Jonas, who is the author of an accompanying editorial.

Shekelle added, "What's needed is several rigorous studies that enroll well-defined patient populations, compare them to a convincing 'placebo' device, and follow these patients for a sufficiently long period of time, using standard measures of outcomes."

The study was funded by the Veterans Affairs Quality Enhancement Research Initiative. The authors' financial relationships are listed in the original article. Dr Jonas has disclosed no relevant financial relationships.

Ann Intern Med.Published online February 13, 2018. Abstract, Editorial

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