It’s the basis of a whole school of thought, variously called New Thought, the Science of Mind or the Law of Attraction, and it (like many things) takes its roots from the concepts expressed in the Kybalion, that:
[b]“THE ALL is MIND; The Universe is Mental.”[/b]
This Principle embodies the truth that “All is Mind.” It explains that The All (which is the Substantial Reality underlying all the outward manifestations and appearances which we know under the terms of “The Material Universe”; the “Phenomena of Life”; “Matter”; “Energy”; and in short, all that is apparent to our material senses) is Spirit, which in itself is Unknowable and Undefinable, but which may be considered and thought of as an Universal, Infinite, Living Mind.
From there, the theory expands that humans, being a high level of self-aware and intellectual mind within “the” Mind, can co-create reality by focused attention of will and imagination, combined with emotion, to create changes in their objective reality.
Anyway, it’s a whole thing and not just a crazed idea (or not crazed IMO anyway) and it’s also happened to me, so it’s quite a recognised phenomena, also happens with healers.