Neurostimulation is rapidly emerging as an important treatment modality for psychiatric disorders. One of the fastest-growing and least-regulated approaches to noninvasive therapeutic stimulation involves the application of weak electrical currents. Widespread enthusiasm for low-intensity transcranial electrical current stimulation (tCS) is reflected by the recent surge in direct-to-consumer device marketing, do-it-yourself enthusiasm, and an escalating number of clinical trials. In the wake of this rapid growth, clinicians may lack sufficient information about tCS to inform their clinical practices. Interpretation of tCS clinical trial data is aided by familiarity with basic neurophysiological principles, potential mechanisms of action of tCS, and the complicated regulatory history governing tCS devices. A growing literature includes randomized controlled trials of tCS for major depression, schizophrenia, cognitive disorders, and substance use disorders. The relative ease of use and abundant access to tCS may represent a broad-reaching and important advance for future mental health care. Evidence supports application of one type of tCS, transcranial direct current stimulation (tDCS), for major depression. However, tDCS devices do not have regulatory approval for treating medical disorders, evidence is largely i nconclusive for other therapeutic areas, and their use is associated with some physical and psychiatric risks. One unexpected finding to arise from this review is that the use of cranial electrotherapy stimulation devices-the only category of tCS devices cleared for use in psychiatric disordersis supported by low-quality evidence.
Bibliographical noteFunding Information:
The authors report the following sources of support for their time working on this project: a grant to Dr. Philip from the U.S. Department of Veterans Affairs (IK2 CX000724); a grant to Dr. Nelson from the Brain and Behavior Research Foundation; grants to Dr. Frohlich from NIMH (R01 MH101547 and MH111889), the Foundation of Hope, the Brain and Behavior Research Foundation, and the Human Frontier Science Program; grants to Dr. Lim from the National Institute on Drug Abuse (R01 DA038984) and the U.S. Department of Veterans Affairs; grants to Dr. Widge from the Harvard Brain Science Initiative, the Brain and Behavior Research Foundation, and the Picower Family Foundation; and support of Dr. Carpenter from Butler Hospital and the Brown Department of Psychiatry and Human Behavior.