Tomorrow I’m giving a presentation on seizures, and I’m reading about how drinking too much water can cause one’s cells to swell, an excess accumulation of water in the brain, seizures, brain damage, coma, and death. I am absolutely disgusted by the number of small children who have died this way because their parents thought it would be a creative punishment to make them drink a gallon of water in one sitting. Also revolting is this story of a woman who died after consuming too much water in an effort to win a radio contest for a Nintendo Wii video game system.
anna in med school 
I thought the excess water flushed the electrolytes out of the system, resulting in various sxs, such as seeming intoxicated, and irregular to non-existent heart beat.
For some time, we had a problem with waterintox as a side effect of longterm psychotropics. It was terrible; the person was always in a perpetual state of thirst. We had to put them on one-to-one just to keep them from stealing and drinking any water they could find (from whatever source [let the reader understand] they could find on the ward).
It was a mess, and I do believe we almost lost of few people. We never did, thanks to a really fantastic crew of nurses and therapy aides. By the time I retired, we’d gotten rid of most of the stuff that could cause it, but we still had some problems from time to time. Everybody responds to meds differently. The most dangerous physicians were the ones who “knew” the effect of the meds, and didn’t want to be confused about individual responses.
Fun times.