One way many states have limited the potential cost of mental health services is by identifying and defining a priority population for those services and then targeting resources to that population. Only by meeting the priority population definition can one access mental health services in most states. Usually, the priority population has been defined by such characteristics as diagnosis and functional limitation, which in theory translate easily to a hierarchy of need.  Sometimes, however, focusing services on a priority population has a perverse ancillary effect.  The complicated diagnostic picture of many of those who are homeless and/or coming into contact with the criminal justice system at times pushes the boundaries of existing priority population definitions. Where financial or capacity pressures are straining the system, people with complex problems are sometimes screened out in favor of those who "only" have a mental illness that clearly fits within the priority definition.

Policymakers and providers need to address the questions of who falls within the priority service population and what to do for those people with serious problems who do not fit established priority categories. It is important that policymakers recognize not just the growing potential of science, medicine, and rehabilitative services, but also their limits. A thorough understanding of these dynamics is difficult for policymakers to achieve, not the least because this is an area in which change is occurring very rapidly. As science and mental health practices advance, policymakers will need to keep pace so that our systems are not - as they are in so many states today - artifacts of a time when far less was known about mental illness and the treatments available for it.

One way to ensure that resources are available to serve people with complex problems who have typically been overlooked by the mental health system and thus are at risk of involvement with the criminal justice system is simply to identify them as a priority population and place them first in line for services instead of last. To do this would mean targeting resources that do not now go to this population. It is a very complicated task to find funding from a variety of federal and state sources for the comprehensive treatment this population is likely to need. Because practice in many places has been to ignore this population and therefore to avoid grappling with the difficulties involved with treating them, expansion of the priority service definition will need to be closely monitored for effectiveness as well as such unintended consequences as the deprioritizing of other needy groups.

Indeed, the possible consequence of expanding the priority population that most alarms advocates, consumers, and many others with a stake in the system is that services for people with mental illness who are law-abiding, adherent to treatment, and in many ways less obvious to those outside the system will fall in priority or even be supplanted by those for the "criminal justice" population. With mandates to serve more difficult patients and no increase in overall mental health system resources, this is one very possible outcome. It is an outcome to be avoided because this law-abiding population, easier to serve though they may be, has been less apparent precisely because the system has worked effectively for them.