According to Osho, transpersonal psychology remains psychology: an objective, mind-centered approach that may synthesize and refine Freud but still studies behavior and mental contents from the outside. It cannot touch Buddhahood, the no-mind, pure awareness, which is utterly subjective and unverifiable by instruments. The 'psychology of Buddhas' is not psychology at all; it is an inner yoga realized only by becoming it.
It’s a nicer, broader psychology that still looks from the outside at the mind, while real awakening can only be known from the inside by being it.