[Pauses a moment to let you prepare yourself for this.]
According to Surgeon's notes the first time someone was taken by it was 650 years after the first people arrived here below the surface. It was referred to as- [Tries to remember the exact wording.] -"the imbalance of the cycle of reuse of energy and 'plugging' of the souls of the planet." It seems to happen most frequently to individuals who are idle or despondent.