Psychiatric illness in a general urban emergency room: daytime versus nighttime population.

Two hundred adults presenting to the emergency room of an urban general hospital were interviewed by a standardized technique to evaluate the existence of a current or previous psychiatric illness. Half of the subjects presented between 8:00 a.m. and 4:00 p.m. (daytime group), and 100 presented between 12:00 a.m. and 8:00 a.m. (nighttime group). In the nighttime population 65% were judged to have current or past psychiatric illnesses. In the daytime population only 36% had current or past psychiatric illnesses. The differences between the 2 populations was highly significant. Fewer than 10% of the 200 patients presented with neuropsychiatric symptoms in their chief complaints.