Abstract
Background: The present thesis is written with the overall aim of
advancing knowledge of criminal offending among individuals with
schizophrenia. This may lead to better and more cost-effective methods
for the prevention of criminal offending and, hopefully, to the reduction
of public fear of mentally disordered persons. One aim of the thesis was
to study risk factors for criminal offending, specifically risk factors
related to antisocial behaviour, low socioeconomic status, problematic
substance use, and low intelligence. Another aim of the thesis was to
study the role of treatment for the reduction of criminal offending.
Methods: A quantitative research design was used throughout the thesis.
Papers I and II were based on data from The Comparative Study of the
Prevention of Crime by Mentally Ill Persons (CSPCMIP), an international,
multi-site follow-up study on forensic and general psychiatric patients
in community care (N = 307). Papers III and IV were based on Swedish
conscription data of 1969-1970 (N = 49 398; participants with a diagnosis
of schizophrenia, n = 377) and follow-up data from the National Hospital
Register and the National Crime Register. The participants of all four
papers were males.
Results: Risk factors for criminal offending present in childhood or
early adulthood were found to be similar for the participants with a
diagnosis of schizophrenia as compared to the participants with no
diagnosis of schizophrenia, specifically risk factors related to
antisocial behaviour and problematic substance use (paper III).
Associations were found between lower verbal intelligence and younger age
of onset of non-violent criminal offending (paper I). A number of
typologies of alcohol use disorder, including the well known Type I/II
Type A/B typology, were replicated (paper II). No associations were found
between inpatient psychiatric treatment and criminal offending (paper
IV).
Conclusions: Criminal offending among individuals with schizophrenia
shares many similarities with criminal offending among individuals with
no mental disorder. It is a complex phenomenon with many factors involved
from a macro to a micro level, some of them out of reach for psychiatric
treatment efforts. It is suggested that criminal offending among
individuals with schizophrenia should be studied within a common
criminological framework. Methods and theories used in criminology may be
of value for the field. Also, forensic psychiatric services may gain from
adopting the what works approach from the correctional services.
