He who brings to the attempt a sufficient degree of informed spiritual development and mental-emotional self-control need have no fear. But he who does not--and such a type is in the majority--may find the solar plexus pouring the force unrestrainedly through his nervous system, inducing permanent insomnia by reason of its pressure upon his brain, until his mind becomes unhinged.

-- Notebooks Category 5: The Body > Chapter 8: Kundalini > # 17