This should come with a warning. Vipassana and other meditation retreats have also caused profound psychosis in people. Be warned about an irreversible mental breakdown. Your mind is unnaturally put in a hyper insensitive environment that it is not meant to be in, nor is it designed to from an evolutionary standpoint. It is designed to stay alert with its environment and defend you from threats, seek mate/food. There were a bunch of posts about this on HN.