When Mike Weisend offers to “hook me up,” I hesitate—and decline. Then I feel bad about it. True, I’ve already arranged to try transcranial direct-current stimulation (tDCS) with Vince Clark’s team in New Mexico a couple of days later, but what kind of journalist refuses any opportunity to try out a technique they’ve been assigned to cover?
The truth is, I’m also a tad apprehensive. Writing in The Week, the journalist Sally Adee described a session of tDCS as a “near-spiritual experience.” Electricity, she went on, “might be the most powerful drug I’ve ever used in my life.” Adee had only positive things to say. For her, the stimulation, which was aimed at enhancing mental focus, silenced her inner voice of self-doubt and turned her from a poor performer at a virtual reality shooting game to a crack shot. But still: There I am in Ohio, hundreds of miles away from anyone who knows me. What if tDCS does change my mind—and I find it hard to deal with? What if there are strange after-effects?
I’ve already discovered that no one knows exactly where the electricity goes once it penetrates the skull, so I start to get even more apprehensive. What if I walk out of the lab feeling anxious or depressed?
When I talk to Clark, he says he’s tried tDCS only once, to “see what it was like.” And it wasn’t even on his head, but on his arm. Brian Coffman, who works with Clark, wires me up and tells me that in all the tests he’s run—somewhere from 250 to 300, off the top of his head—he’s never had a volunteer who’s reported anything more dramatic than a headache. But when he gives me a pre-stimulation survey that asks how “guilty,” “irritable,” or “excited” I’m feeling, I have to wonder why they need to know. Coffman says they don’t intend the procedure to change these psychological variables, but a brain region only about five to 10 centimeters away from the part they’re planning to stimulate is linked to mood. I’ve already discovered that no one knows exactly where the electricity goes once it penetrates the skull, so I start to get even more apprehensive. What if I walk out of the lab feeling anxious or depressed? What if that state of mind doesn’t lift?
Like a dose of a chemical drug, a session of tDCS doesn’t produce the same reaction in all people. “Some people are greatly affected” in terms of changes in mental performance, says Weisend’s colleague Andy McKinley. “Some have almost no response.” He and his team have been trying to figure out why. They’ve looked at IQ and personality test scores, and asked about their volunteers’ backgrounds. So far, all they’ve found is that people who rank as more “agreeable” on the personality tests seem to show a bigger response to tDCS. Whether or not they experience different subjective psychological effects isn’t known.
In my case, I needn’t have worried. During the stimulation, and afterwards, I feel no different (and my performance on the task doesn’t improve that much after stimulation, either). It’s a bit of an anticlimax and I feel even worse for not trying tDCS at Weisend’s lab too. Maybe I’m disagreeable. Maybe a tDCS kit wouldn’t ever supercharge my brain, as it might for other people (though of course it’s very hard to tell from just one trial). But as someone who prefers to limit their mind-altering drugs to alcohol and caffeine, the absence of any effect from tDCS leaves me feeling not cheated, but relieved.