Level 1 psychiatric emergency services. The tools of the crisis sector.

Psychiatric emergency services have become an increasingly important element in the mental health system. Many approaches to delivering these services have been described but no unifying constructs have emerged. This article reviews the range of psychiatric emergency settings including their structure and functions, the evidence of their benefits to the system, and the controversies surrounding their use. Categorization by capability is proposed as a means of improving the quality and consistency of assessment and treatment. Regional consolidation is proposed as a means of accomplishing these improvements while containing costs.