Public health consequences of different thresholds for the diagnosis of mental disorders.

The acceptance of subthreshold disorders in psychiatry is a controversial topic with multiple implications for public health policy. Using subthreshold depression as an example, we provide documentation based on data from epidemiologic and clinical studies suggesting that subthreshold conditions are not uncommon, there is significant associated disability (with significant societal costs), and the course of illness often leads to the development of the full-blown disorder. The potential societal benefits of developing and testing low-cost, low-risk, and nontraditional treatments are considered. The recommendations are to match treatment intensity and cost with severity level in a staged approach.