One key characteristic of depression is overly-strengthened connections between brain circuits in certain regions of the brain — particularly those involved in concentration, mood, conscious thought, and the sense of self. And in fact, this may be part of the reason that electroconvulsive therapy, which involves placing electrodes on the temples and delivering a small electrical current, can help some severely depressed people — by tamping down on some of this traffic.
"In the depressed brain, in the addicted brain, in the obsessed brain, it gets locked into a pattern of thinking or processing that's driven by the frontal, the control center, and they cannot un-depress themselves," David Nutt, the director of the neuropsychopharmacology unit in the Division of Brain Sciences at Imperial College London, told me.
Visualization of the brain connections in the brain of a person on psilocybin (right) and the brain of a person not given the drug. Journal of the Royal Society Interface
Nutt has been one of the pioneering researchers in the field of studying how psychedelics might be used to treat mental illness. He said that in depressed people, these overly-trafficked circuits (think West Los Angeles at rush-hour) can lead to persistent negative thoughts. Feelings of self-criticism can get obsessive and overwhelming. So in order to free someone with depression from those types of thoughts, one would need to divert traffic from some of these congested ruts and, even better, redirect it to emptier highways.
Which is precisely what psychedelics appear to do.
"Psychedelics disrupt that process so people can escape. At least for the duration of the trip they can escape about the ruminations about depression or alcohol or obsessions. And then they do not necessarily go back," said Nutt.
A 4-hour trip, a long-lasting change
"Medically what you're doing [with psychedelics is] you're perturbing the system," Paul Expert, who co-authored one of the first studies to map the activity in the human brain on psilocybin, told me over tea on a recent afternoon in London's bustling Whitechapel neighborhood.
Expert, a physicist at the King's College London Center for Neuroimaging Sciences, doesn't exactly have the background you'd expect from someone studying magic mushrooms.
But it was by drawing on his background as a physicist, Expert told me, that he and his team were able to come up with a systematic diagram of what the brain looks like on a psilocybin trip. Their study, published in 2014, also helps explain how altering the brain temporarily with psilocybin can produce changes that appear to continue to develop over time.
When you alter how the brain functions (or "perturb the system," in physicist parlance) with psychedelics, "that might reinforce some connections that already exist, or they might be more stimulated," Expert told me.
But those changes aren't as temporary as one might expect for a 4-hour shroom trip. Instead, they appear to catalyze dozens of other changes that deepen in the for months and years after taking the drug.
"So people who take magic mushrooms report for a long time after the actual experience that they feel better, they're happier with life," said Expert. "But understanding exactly why this is the case is quite tricky, because the actual trip is very short, and it's not within that short span of time that you could actually have sort of new connections that are made. That takes much more time.”
New York University Bluestone Center for Business Insider