Although the exact cause of NDE is not yet understood, examining the scientific literature, there are currently three broad views proposed to account for the causation of NDEs. Some researchers have proposed that NDE occur as a consequence of a brain based chemical disorder, others have proposed that this may be a psychological stress event related to becoming close to death and a group of other researchers have proposed that NDE may support a 'spiritual' or transcendental event. The most favourable scientific arguments have largely centred around the first two concepts - .