Introduction

The United States’ incarceration rate of its national population is the highest in the world.¹ The percentage of incarcerated individuals with a mental illness is substantial, with 10% to 15% of inmates suffering from a serious mental illness (SMI).² Two-thirds of sentenced jail inmates met criteria for drug dependence or abuse.³ Many inmates experience both mental illness and a substance use disorder as co-occurring conditions.

Multiple reasons account for the rise in the number of individuals with mental illness entering the criminal justice system. First, in the 1960s, a movement began to deinstitutionalize individuals with mental illness and discharge them from psychiatric hospitals to the least restrictive environment. As a result, large numbers of individuals previously treated in an inpatient setting were released into the community with a resulting decrease in inpatient psychiatric hospital beds. Second, during the 1970s, the United States increasingly turned to punishment of individuals with a drug offense rather than treatment. As a result, drug-related offenses increased with a subsequent rise in arrests and incarcerations. Third, during this same relative time period, judges were given less discretion in imposing sentence lengths as legislatures increasingly mandated determinate and fixed sentencing to demonstrate a “get tough on crime approach.” Fourth, during the 1960s and mid-1970s, civil commitment laws were substantially reformed, making involuntary commitment of individuals with mental illness more difficult.⁴ As a result of these, and other factors, a ballooning number of people with mental illness are finding their way into a jail or prison, rather than a hospital setting.

Criminalization of mental illness refers to the inappropriate diversion of those with mental problems to the criminal justice system rather than to treatment.⁵ To help address this mismatch of people and resources, public policy is shifting to finds ways to divert these individuals away from potentially long and costly incarcerations and into appropriate and effective treatment. An increasing use of the principle known as “therapeutic jurisprudence” is being utilized as an alternative approach to the mass incarceration of individuals with mental illness. Core concepts of therapeutic jurisprudence include the application of law in the most appropriate way to benefit all individuals, increasing therapeutic aspects of legal interventions while decreasing antitherapeutic aspects, and protecting the due process rights of both offenders and victims.⁶

In general, individuals eligible for diversion from the criminal justice system are those with a treatable mental and/or substance use disorder that can be safely maintained in the community. Munetz and Griffin⁷ proposed the Sequential Intercept Model (SIM) as a useful framework to conceptualize a series of “points of interception” where individuals with a mental illness may be prevented from entering or progressing further into the criminal justice system. These authors acknowledge that individuals with mental illness who demonstrate criminal behavior unrelated to their mental illness should be held accountable for their behavior; however, people with mental illness should not be arrested or detained longer than others only because of their mental illness.⁷ The five intercept points proposed by the SIM are summarized in Table 11.1.

This article focuses primarily on the first three SIM intercept points as related to jail diversion and reviews types of diversion programs, research outcomes for diversion programs, and important components that contribute to successful diversion.