There is also growing evidence that microdosing psychedelics like LSD or psilocybin can be beneficial:
https://www.forbes.com/sites/willburns/2018/02/26/the-beckle...
What's happening in the brain exactly that gives people an advantage? What is the brain science behind microdosing LSD?
The effects of microdosing in the brain are not known, which is why I am setting up an international research program to investigate how microdosing, both acutely and after repeated doses, may produce changes in brain function. Our results with higher doses of LSD show that LSD revealed important changes in the way different brain regions communicate with each other, resulting in a more integrated and fluid brain state. The Beckley/Imperial Research Program found that LSD makes the brain much more connected and flexible.
Both the psilocybin and LSD studies showed a decrease in blood flow to the “default mode network” (DMN), meaning there was less activity in the parts of the brain that repress other parts that maintain the normal, restricted status quo. The DMN is activated when the mind is wandering, not committed to a task, but overlooking the past and planning the future, and thinking about one’s self and one’s emotional state. An overactive DMN underlies the excessive rumination associated with psychological disorders such as depression, anxiety, addiction and post-traumatic stress disorder. A microdose likely lessens the rigidity of the DMN, making the brain more flexible.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5853825/
Second, like Huxley’s cerebral reducing valve and Freud’s ego, EBT argues that the DMN’s organizational stronghold over brain activity can be both an evolutionary advantage and a source of pathology. “It is argued that this entropy-suppressing function of the human brain serves to promote realism, foresight, careful reflection and an ability to recognize and overcome wishful and paranoid fantasies. Equally however, it could be seen as exerting a limiting or narrowing influence on consciousness” (Carhart-Harris et al., 2014, p. 7). Carhart-Harris et al. (2014) point out that neuroimaging studies have implicated increased DMN activity and RSFC with various aspects of depressive rumination, trait neuroticism, and depression. “The suggestion is that increased DMN activity and connectivity in mild depression promotes concerted introspection and an especially diligent style of reality-testing. However, what may be gained in mild depression (i.e., accurate reality testing) may be offset by a reciprocal decrease in flexible or divergent thinking (and positive mood)” (Carhart-Harris et al., 2014, p. 10).
Third, consistent with both psychoanalytic and filtration theory, is the notion that psychedelic drugs’ capacity to temporarily weaken, collapse, or disintegrate the normal ego/DMN stronghold underpins their therapeutic utility. “Specifically, it is proposed that psychedelics work by dismantling reinforced patterns of negative thought and behavior by breaking down the stable spatiotemporal patterns of brain activity upon which they rest” (Carhart-Harris et al., 2014, p. 1).