Researchers' perspectives on scientific and ethical issues with transcranial direct current stimulation: an international survey

In the last decade, an increasing number of studies have suggested that transcranial direct current stimulation (tDCS) may enhance brain function in healthy individuals, and ameliorate cognitive and other symptoms in patients suffering from various medical conditions. This, along with its presumed safety, simplicity, and affordability, has generated great enthusiasm amongst researchers, clinicians, patient populations, and the public (including a growing "do-it-yourself" community). However, discussion about the effectiveness and ethics of tDCS thus far has been confined to small groups of tDCS researchers and bioethicists. We conducted an international online survey targeting the opinions of researchers using tDCS who were asked to rate the technique' s efficacy in different contexts. We also surveyed opinions about ethical concerns, self-enhancement and public availability. 265 complete responses were received and analyzed statistically and thematically. Our results emphasize the potential uses of tDCS in clinical and research contexts, but also highlight a number of emerging methodological and safety concerns, ethical challenges and the need for improved communication between researchers and bioethicists with regard to regulation of the device. Neither the media reputation of tDCS as a "miracle device" nor concerns expressed in recent neuroethical publications were entirely borne out in expert opinion.