This is what the media does! They are referencing the article discussed here, where Nathan Whitmore (ohsnapitsnathan) points out that due to the unusual electrode configuration, “…the current density at the cathode is actually greater than at the “active” electrodes…).

Who ever thought this was a good idea? A form of electrical brain stimulation was first used to treat melancholy in the 19th century.

Melancholy isn’t even a thing. In the 1960s, tDCS became briefly fashionable when it was shown that it could alter the excitability of neurons in the motor cortex. More recently, it’s been used to increase or decrease cortical activity with the aim of alleviating depression or insomnia.

Hopefully, doctors will exercise extreme caution with the treatment now the possibility of detrimental effects has been raised. Are you kidding? People are out there zapping themselves – you can buy a tDCS kit online for less than £100. You can even find instructions to make your own.

So this isn’t the end for tDCS? Probably not. And a similar application, but with alternating current – tACS – is also being researched.

Do say: “The effect of electrical stimulation on the brain has fascinated scientists for centuries, and yet it remains so little understood.”

Don’t say: “My IQ’s gone down? I’m shocked.”

Source: Warning: transcranial direct current stimulation can do your head in | Science | The Guardian