Patients who bring weapons to the psychiatric emergency room.

The personal characteristics of patients who brought weapons to a university hospital-based psychiatric emergency room were examined. During 14 months following implementation of a routine weapon-screening procedure, 37 (4%) of 1012 psychiatric emergency room patients were found to have weapons. These patients did not differ significantly from a randomly selected control group of non-weapon-carrying patients on a variety of demographic and clinical variables often associated with violence potential, although the weapon-carrying patients were more likely to be male and have a history of substance abuse. The heterogeneity of personal characteristics of weapon-carrying patients is likely to make them difficult to distinguish clinically from other patients. The findings have important implications for maintaining safety in the psychiatric emergency room.