Warning over electrical brain stimulation

Given the option, would you want to think faster and have sharper attention? Research suggests that electrical brain stimulation kits could have just those effects. But now some companies are selling such devices online, leading to calls to regulate the technology. It may sound too good to be true but scientists say the technology is promising.
 
Transcranial direct current stimulation (TDCS), which passes small electrical currents directly on to the scalp, stimulates the nerve cells in the brain (neurons). It’s non-invasive, extremely mild and the US military even uses TDCS in an attempt to improve the performance of its drone pilots. The idea is that it makes the neurons more likely to fire and preliminary research suggests electrical simulation can improve attention as well as have a positive impact on people with cognitive impairments and depression.
 
It has also been shown to increase performance in a maths task, an improvement which was still in place six months later. The scientist behind this work is Dr Roy Cohen Kadosh from the University of Oxford. He uses TDCS to look at how cognitive functions improve.