The importance of cognitive deficits for forensic mental health patients with schizophrenia or schizoaffective disorder

Abstract

Forensic Mental Health Services (FMHS) provide care and treatment to a minority of people with mental illness like schizophrenia or schizoaffective disorder, who come into contact with law enforcement agencies (Kennedy et al., 2006; McFadden 1999). Within the Republic of Ireland and other jurisdictions, most forensic mental health patients have a diagnosis of schizophrenia or schizoaffective disorder (Jansman-Hart et al., 2011). Cognitive impairment is increasingly recognised as a key feature of these disorders (Kahn and Keefe, 2013). To date, the importance of cognitive impairments for patients hospitalised within FMHS has scarcely been examined. This thesis seeks to address this gap in knowledge in two ways. First, by clearly describing the problem, namely investigating the prevalence and importance of cognitive impairments for forensic patients with schizophrenia and schizoaffective disorder. Second, by exploring what can be done to improve patients cognitive impairments.

The first chapter provides an introduction and describes FMHS and the importance of cognitive impairment for understanding functional outcomes for patients with schizophrenia and schizoaffective disorder. This chapter draws primarily from research concerning the relevance of cognitive impairment for functional outcomes amongst non-forensic patients (Kahn and Keefe, 2013). The association between mental disorders like schizophrenia and schizoaffective disorder and acts of serious violence like homicide is introduced, as are studies examining a link between cognitive impairment and acts of violence. In addition, pharmacological and psychological approaches for improving cognition are described. The chapter concludes by providing an outline of the three empirical studies which form the heart of the thesis.

The second chapter describes the first empirical study, which examines the relationship between cognitive impairment and unplanned reactive inpatient violence. Multivariate analysis demonstrated that cognitive impairment could account for a large proportion of the variance of inpatient violence. For this national cohort the mean composite score on a neuropsychological battery specific to the cognitive impairments experienced by patients with schizophrenia and schizoaffective disorder was more than three standard deviations (SD) lower than the nonclinical population mean.

The third chapter describes an empirical study examining the relationship between the potentially harmful effects of pharmacotherapy (specifically anticholinergic burden), cognitive impairment, and the ability to benefit from multimodal treatment programs. The results of this study indicate that the cognitive impairment experienced by forensic mental health patients is associated with anticholinergic burden, and that anticholinergic burden was associated with treatment progression only via cognitive impairment.

The fourth chapter describes a protocol for a registered intention to treat (ITT) randomised controlled trial (RCT) of cognitive remediation training (CRT) for most of a national cohort of patients with schizophrenia or schizoaffective disorder. The chapter provides a review of meta-analyses of randomised controlled trials of (CRT) involving non-forensic patients.

The fifth chapter is an empirical study describing the completed RCT. Our RCT is one of only a handful of RCTs which have been conducted within FMHS. The key findings were that the group receiving CRT showed significant improvements on the primary measure of cognition, and secondary measures of cognition including visual and working memory, compared to a waiting list control group receiving treatment as usual (TAU). Cognitive improvements were maintained during the eight-month follow up period. Eighty-five precent of patients said they benefited from participating in CRT when provided with a confidential exit interview.

The sixth and final chapter reviews the thesis in its entirety. Each study is linked with existing theories and knowledge explaining how they progress the field. The strengths and limitations of the thesis are also reviewed. The chapter concludes by taking a prophetic glance to the future outlining the many ways, which a focus on cognition could lead to changes in care and treatment for patients with schizophrenia and schizoaffective disorder.