Approximately 16% of the U.S. prison population suffers from a severe mental illness (1); however, interventions for mentally ill offenders lack therapeutic specificity. More specifically, interventions for mentally ill offenders have generally applied a biopsychosocial treatment model (2) with minimal focus on criminological treatment needs. However, it has been well documented that effective criminal rehabilitation with non-mentally ill offenders must incorporate cognitive behavioral interventions that target criminogenic needs (e.g., criminal thinking styles, criminal attitudes) to be effective (3,4,5). Although borrowing interventions developed for non-mentally ill offenders and applying them to mentally ill offenders is insufficient, identifying effective interventions for mentally ill offenders is problematic due to the multitude of factors that contribute to the criminal behavior (e.g., issues of mental illness and criminal propensity). Therefore, when mental illness and criminal behavior co-occur "it is imperative" that interventions attend to both the mental disorder and the criminal behavior" (6 p. 143). The delivery of effective services that reduce jail or prison recidivism (i.e., services aimed at reducing criminal behavior and subsequent reincarceration) is particularly relevant for this population to avoid a disruption of the therapeutic services and community integration that is necessary for overall improved mental health outcomes (see 7). Although interventions have proven effective in reducing criminal recidivism with non-mentally ill offenders (e.g., 3,4), there is a paucity of information regarding effective treatment and service strategies specifically designed for mentally ill offenders. In fact, so little is known about mentally ill offenders compared to their non-mentally ill counterparts, there is no data to guide the development of services. As a result, interventions have not been tailored to meet both the mental health and criminal behavior needs of this population. Thus, it is proposed that a multifaceted intervention is needed to meet the needs of mentally ill offenders. The long-term aim of this investigator is to develop an empirically supported modularized intervention for mentally ill offenders that targets both psychiatric symptoms and criminal behavior. Such an intervention would incorporate biopsychosocial modules to treat mental illnesses; however, little is known about the criminal behavior treatment needs of mentally ill offenders. A promising line of research with regard to therapeutic interventions for non-mentally ill offenders is the prevalence of thinking styles and attitudes that contribute to criminal behavior (e.g., 8,9,10). Such cognitive-behaviorally based programs have resulted in effective outcomes for the general population of offenders (3,4,5); however little is known about the extent to which such thinking styles and attitudes occur in mentally ill offenders. Thus, the objective of this study is to identify the criminal thinking styles and attitudes exhibited by mentally ill offenders as a precursor to the development of specialized interventions and services. Participants for this study will consist of 400 incarcerated adult mentally ill offenders. Participants will be administered the Psychological Inventory of Criminal Thinking Styles (PICTS; 11), a measure of criminal thinking styles, and the Criminal Sentiments Scale-Modified (CSS-M: 12), a measure of attitudes, values, and beliefs that are related to criminal behavior (13). The proposed study has two Aims. First, Confirmatory factor analyses will be utilized to determine if the underlying factor structure of mentally ill inmates responses to the PICTS and CSS-M resemble the structure underlying non-mentally ill offenders. Second, cluster analyses will be utilized to identify subgroups of mentally ill offenders based on PICTS and CSS-M profiles and psychiatric symptoms. The proposed study lays the foundation for a treatment module specifically targeting the criminal behavior needs of mentally ill offenders. [unreadable] [unreadable]