Cranial Electrotherapy Stimulation (a.k.a. cranial-electro stimulation and transcranial electrotherapy) is the application of small electrical currents (e.g.1mA) to the brain externally via electrodes on the scalp. It has been in use since the late 1700s.
It is (or was) used to treat a wide range of disorders, including insomnia, depression, anxiety etc etc.
The mechanism of action is unknown - and several recent studies have found that it's ineffective for almost all of the conditions which it has traditionally been used to treat. It may have some benefit for treating source )but clear evidence for its effectiveness is lacking (
Note: A newer version of the treatment, first tested in humans in 2008, is called Transcranial Random Noise Stimulation and uses randomised noise signals to the brain instead of sine-wave alternating current. Its Mechanism of Action is also unknown, and it has not yet found clinical application.
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