Karl Deisseroth: “Becoming a psychiatrist wasn't even on the map”
Meeting a patient with delusions made Karl Deisseroth want to understand brain dynamics better. Since then he has developed several ground-breaking methods. Read an interview with one of the 2026 Nobel laureates in Physiology or Medicine, published in KI's magazine Medicinsk Vetenskap in 2015.
Text: Anders Nilsson, first published in Medicinsk Vetenskap nr 4 2015
Name: Karl Deisseroth.
Title: Professor of Bioengineering and of Psychiatry and Behavioral Sciences at Stanford University, USA.
Currently: Foreign Adjunct Professor at Karolinska Institutet**, where there are now research environments for both optogenetics and transparency technique – two new areas of research developed by Deisseroth.
** Since this article was published, Karl Deisseroth has left his affiliation at KI.
“The man was staring at me. He had a schizoaffective disorder and suffered from severe delusion. At this occasion it included me – he was screaming at me; he was loud and upset! It was the early 1990s, I was studying at Stanford School of Medicine and had just started my mandatory internship in psychiatry. I came there without particularly high expectation because I already knew what specialisation I wanted to pursue: neurosurgery. It was the most challenging thing I could imagine. Becoming a psychiatrist wasn't even on the map for me.
But meeting the patients in psychiatry made me revaluate everything. Particularly the meeting with this man. The situation provoked strong feelings and new thoughts within me. It was awful to see how much he suffered and how little the health care system could do for him. He had been ill for many years, all possible treatments had been tested, none of them helped.
I was also struck by the realisation that this man's brain actually didn't have any damage. I knew that no test – neither EEG, MRI, PET nor any other technique – would show anything other than his brain being totally normal.
Still he lived in his own deluded world. It was something else, something more subtle that was wrong: the system dynamics. It fascinated me and became crucial to my career choice. As a neuroscientist I have focussed on the dynamics of the brain. The questions that arose at that meeting eventually also led to the methods and techniques that I have developed: optogenetics and the transparency technique.
And as a clinician I obviously never became a neurosurgeon but a psychiatrist.”
Transparency technique in brief
Dead tissue is processed so that it becomes transparent. This allows the researchers to examine entire organs, such as the brain, without having to cut through the tissue.