Psychedelic drugs’ impact on the brain’s level of consciousness is the topic of a new study by researchers at the University of Sussex. A measure called ‘global signal diversity’ that measures the electrical activity of the brain has already shown its usefulness as a measure of ‘conscious level.” For example, this measure has been used to show that people demonstrate more diverse neural activity while they are awake than while sleeping. In this study, neuroscientists have witnessed a rise in neural signal diversity in individuals under the influence of psychedelic drugs, compared to their normal waking state. This is the first study to prove that brain-signal diversity is higher than in the conscious, awake and aware, baseline state. Researchers believe that more research is needed using more sophisticated and diverse models to advance research in this area. The research team stressed that the outcomes do not mean that the psychedelic state is a better or more desirable state of consciousness. Rather, it revealed that by applying a simple mathematical measure of signal diversity the psychedelic brain state is distinctive and relatable to other universal changes in the conscious level such as sleep and anaesthesia. The three psychedelic drugs examined in the study presented similar changes in signal diversity, despite their quite different pharmacology. This fact is reassuring to the researchers that the study results will prove to be robust and repeatable and will aid informed discussions about the carefully controlled usage of these drugs, for example in treating severe depression and in understanding the occurenc of hallucinations.