Understanding the potential relationships between serious mental illness, substance use disorders and crime amongst psychiatric inpatients

Abstract

Despite common factors shared by individuals who present with substance abuse and psychiatric comorbidities, research shows that this is a heterogeneous population with varying types and levels of mental disorders and dependencies. Within this context, this study analyses various characteristics of psychiatric inpatients who are diagnosed with substance use disorders, with special interest to their relationship with mental illness and crime. A mixed method of research is adopted. Quantitative research is applied through retrospective case note reviews of patients admitted to Dual Diagnosis wards at Mt. Carmel Hospital in 2015 and 2016. A database including seventeen different categorical variables is created. This permits the use of cross-tabulations and chi-square tests in order to compare variables and establish potential relationships. Statistical results are further complimented by qualitative data that is derived from six semi-structured interviews with experts in the field. Results demonstrate that the majority of the population are male, unemployed and poly drug-users with negative childhood experiences and criminal histories that are dominated by theft, drug-related crimes and violence. In line with dual-diagnosis models, this study confirms that substance use can lead to mental illness and vice versa. It also verifies the complex needs and vulnerability of inpatients who suffer from dual-diagnosis. Statistically significant relationships indicate that inpatients who suffer from serious mental illness and substance use disorders have heightened risks of child physical and sexual abuse, out of home care, family history of mental illness, long-term unemployment, recurrent psychiatric hospitalisation over longer periods of time and involuntary admissions. The relationship between heavy drug-use and crime is evident but the crimes of those with substance use disorder only are not significantly different from those who are also diagnosed with serious mental illness; this result may be affected by their substance dependence. Females, irrespective of their diagnostic criteria, are also identified as a vulnerable group. They are more likely to have childhood traumas, to be early school leavers and in longterm unemployment, to have a family history of substance abuse, to work as prostitutes and to have involuntary admissions. Significant associations are also proven between early school leaving, unemployment and crime. These clarify the interplay between different factors that may affect the relationship between substance use disorders, mental illness and crime.