I would agree that brain chemistry can be manipulated using different substances. LSD is just one of many that are proven to alter the brain's physiological state. In fact, most of what we experience in our environment affects brain physiology in one way or another. However, my contention is that the mind is also capable of inducing physiological changes, without the need of external agents, and in such a way as to reproduce any and every physiological change that such external agents, inlcuding prescription psychiatric meds, is able to affect, at least within the physical limits of a given physiology. I would even go so far as to say that a properly disciplined mind would not only be able to reproduce physiological conditions, but also counteract externally induced changes to some degree.

Granted it takes a lot of training and discipline, but it is doable.