Interphase psychosis is a disease, a degenerative psychological condition caused by exposure to the distortion of normal space and time that is known as interphase. Humanoids, particularly Humans, are susceptible to this condition, which is caused by energy effects stimulating nerve endings throughout the victim's body. With the nervous system stimulated so, an afflicted being will suffer severe pain, wild emotional states and eventually a total nervous breakdown. As panic and anger manifest themselves, many victims will be overcome by murderous rage. The condition can be effectively halted by specially prepared agents that deaden the nerve endings that are stimulated by the spatial anomaly. (TOS episode & Star Trek 5 novelization: The Tholian Web; TOS - The Tholian Webs comics: "Part 1",