The case suggested that MDMA has the potential to "influence a person's values and priorities," the authors wrote in a case study about Brendan. They hypothesized that if extremist views are fueled by fear, anger, and cognitive biases, they could potentially be treated with drugs.
It's interesting to learn, what this paragraph seems to suggest, that for some people holding extremist views is actually the result of mental illness. It is probably hard for people to realize and/or even admit that they are ill until something drastic happens.