Has anyone heard anything about Cranial electrotherapy stimulation (CES) for reducing pain or for inducing sleep?
The info says it's FDA approved for insomnia, depression and anxiety and shows promise for FM. This excerpt is meant more specifically for addiction, but talks about it more broadly too.
Cranial electrotherapy stimulation (CES), (also known as “electrosleep”, “transcranial electrotherapy” and by many other names), involves a form of treatment that sends low intensity microcurrent (under 1 milliampere) to the brain.  CES devices function differently from other biomedical electronics, such as deep brain stimulating electrodes (which prevent seizures and hand tremors)  and heart pacemakers. While those instruments require surgical implantation, CES operates non-invasively. Designed for home use, the devices deliver current to the brain via a hand held machine to electrodes attached on or behind the ears. 
Uses for Brain Health
A wide body of research suggests that the technique effectively treats insomnia, depression and anxiety (the only FDA approved uses). Scientific data also shows promise for other conditions such as pain, tension/migraine headaches, fibromyalgia, and ADHD. CES might also provide benefits for chemical dependencies (such as street and prescription drugs, alcohol, and tobacco); that is, it might help the insomnia, anxiety and depression that often manifest during withdrawal. [4,5]
Individual responses may vary, but most users report reduced symptoms (such as anxiety) after their first or second treatment. During use, patients often experience pleasant mental states with increased muscle relaxation yet enhanced mental clarity. They might also feel a pulsing or tingling, sensation in their earlobes, (considered normal), which setting adjustments can alleviate. Positive effects after a single treatment may last up to two days and effects usually become cumulative. 
Researchers don’t fully understand mechanisms involved, but theorize that CES electrical current helps reestablish optimal brain chemistry and improves efficiency of neural connections.  One example of research supporting this theory involves electrical engineering simulations conducted by researchers at the University of Texas, Austin. Their brain mapping techniques suggested that minute amounts of current traveled to the brain’s thalamus, enough to enable release of neurotransmitters.  Other research conducted by North Dakota State University utilized EEG techniques to quantify changes during administration of CES versus sham treatment. The research showed frequency distribution shifts suggestive of beneficial changes. 
Based on current and ongoing research, neuroscientist Dr. James Giordano postulates that CES microcurrent travels to the base of the brain (the brainstem), activating clusters of nerve cells which make the brain chemicals serotonin and acetylcholine. Serotonin is linked to relaxation  while acetylcholine is linked to body processes not under conscious control while at rest.  Released by nerve cells at the synapse, these neurotransmitters influence pathways within the brain and spinal cord that inhibit arousal and agitation. The resulting “fine tuning” helps the nervous system to restore homeostatic balance and possibly creates brain patterns known as alpha rhythms. Measurable via brain wave recordings (called EEG); scientists often associate alpha states with enhanced mental focus and relaxation. Neurological processes linked to alpha states seem to reduce stress, stabilize mood, and exert control over certain types of pain.
CES has an excellent safety record, few side-effects, and works well for all age groups. CES users sometimes have temporary headaches, lightheadedness, skin irritation from electrodes and rare paradoxical reactions (such as excitement, anxiety, sleep problems, or increases in pre-existing depression). Pregnant or lactating women, people with implanted bioelectrical devices, or those taking supplements or medications affecting the brain or vascular system should first consult with a physician.  Of 17 follow-up studies conducted up to two years after treatment, none showed negative effects.  Very few major short or long-term problems have therefore been found, and several of the devices carry FDA approval. 
According to Dr. Daniel Kirsch, an authority on electromedicine and Chairman of Electromedical Products International, research shows CES to be safe, having good results for a range of brain based disorders. He believes the evidence supports use as a first line treatment for issues it effectively treats.
Writing on behalf of the Houston VA Pain Management Program, psychologists Dr. Gabriel Tan and Dr. Julie Alvarez argue for integrating CES and self hypnosis into multidisciplinary pain treatment programs. Clinic patients usually have intense chronic pain, not helped by analgesics; additionally, they often travel long distances for treatment, having limited means, and social problems. Seeing pain mainly as a physical problem and lacking resources for long treatments, patients often want tangible, fast results. CES and self hypnosis combined therefore meet the need, as they take little time and provide quick results. After getting some measure of relief, patients are often more willing to accept additional psychological help as a part of their treatment plan. 
Physician advocates Dr. Marshall F. Gilula and Dr. Paul Barach (in an editorial published by Southern Medical Journal) assert that the device can be a valuable treatment for the approved uses of anxiety, depression, and insomnia. While physicians usually treat those problems with psychoactive drugs, they point out that the medications often pose safety concerns; that is, they have potential for side-effects or dependency.  (FDA warnings for selective serotonin reuptake inhibitors used for depression, serve as a prime example.)  Like psychoactive drugs, CES does require ongoing medical supervision, but it doesn’t have the same potential for problems. Ultimately, they maintain that CES is of great value as a safe, non-drug alternative which can reduce or sometimes even replace medication use. They say that while CES is not a miracle cure, it is at least worthy of consideration.