Risk factors for violent behavior in people with psychotic disorders

This dissertation has expanded knowledge of violent behavior in people with schizophrenia and other psychotic disorders by showing that: (a) it is often illness-related; (b) the role that cognition and brain structure play in its development is negligible; and (c) all drug use increases the likelihood of it occurring. These results have important clinical and legal implications. First of all, therapists should always screen for delusions, impulsivity, drug use, poor illness insight and treatment nonadherence when trying to predict or manage violence in their patients. Better prevention not only means that less harm will come to future victims, but it will also reduce the stigmatization of patients and the economic costs to society at large. Finally, the results suggest that – in the absence of traumatic brain injury – it is inappropriate to explain violent crimes committed by defendants diagnosed with psychotic disorders from neuropsychological test scores or the size of brain regions. This is relevant, as the use of neuroscientific evidence in criminal proceedings has grown sharply in the Netherlands over the past two decades.