In Psychology: "Do Symptoms of Schizophrenia make People More Likely to Commit Violent Crime?"

Question Mark Picture.jpg

By Oxford University Experimental Psychology graduate, Chloe. Chloe is currently undertaking a Masters in Clinical Forensic Psychology.

We often see headlines about those with mental health difficulties who have committed crime. If not a news headline, there are often gripping plots in our favourite shows or films that depict those with mental illness in a violent light. Does this necessarily mean that all those with mental illness commit crime? Does it even mean that those with such illnesses are more likely to commit crime? These kinds of questions are important, as perceptions of those with mental health problems contribute to stigma which can be detrimental to the individual when seeking help or work, as well as on a social level. However, these questions are difficult to answer, especially with a host of different mental health disorders (e.g. anxiety, depression, schizophrenia) and differences even within mental disorders themselves as people experience varying symptoms.

 It's more helpful to break these questions down into how specific disorders can relate to specific facets of crime. Take, for example, schizophrenia and its relationship with violent crime. Schizophrenia is a mental health condition typically characterised by psychosis, such as hallucinations and delusions. Schizophrenia may also be accompanied by so-called ‘negative symptoms’, such as social withdrawal.

At present, research has shown that there is an elevated rate of violent crime committed by those with schizophrenia compared to the general population. Whilst the majority of violent crime is not committed by those with schizophrenia, the risk of violent outcomes is higher in those with than without the disorder. However, taking this link at face value implies that schizophrenia itself and its symptomatology are responsible for increased rates of violent crime, which may not be the case. There are factors that complicate answering whether symptoms of schizophrenia are related to crime and, if so, in what way. These factors are ‘confounding factors’ which increase the risk of violence in those with schizophrenia. When we control for these factors, the risk of violence in those with schizophrenia is actually reduced.

To fully address how a mental health disorder impacts crime, we need to breakdown what the risk factors for crime are and therefore what confounding factors need to be controlled for. In schizophrenia, some confounding factors are: substance abuse, such as alcohol and drug misuse; antisocial personality traits, such as not adhering to societal norms or breaking the law; psychopathic traits, such as being callous or lacking empathy. Now, let’s look at how each of these impacts the risk of violent crime in schizophrenia.

  • Substance abuse

Substance abuse has been shown to increase the risk of violence in schizophrenia by as much as four times. There may be several reasons for this, for example disinhibition from being drunk may make people more likely to commit crime. Moreover, those who abuse substances may be less likely to take their medication and continue to abuse substances unmedicated, which means that their symptoms could be worse and increased distress could lead to a violent offence.

  • Antisocial personality

Some people’s antisocial traits can warrant a diagnosis of ‘antisocial personality disorder’. This involves a disregard to the law or the rights of others, often with a history of crime and skipping school. Research has shown that some people living with schizophrenia also reach the diagnostic threshold for antisocial personality disorder. In some of these cases, antisocial personality disorder further increases the risk for crime. In at least some of these instances, it is possible that the individual would be violent anyway, whether they had schizophrenia or not.

  • Psychopathy

Psychopathy is another personality disorder, which can involve impaired empathy and lack of remorse. Studies have shown a strong association between psychopathy and violent offending in those with schizophrenia. Amongst those with schizophrenia, those with high psychopathic traits are at a higher risk of committing violent crime than those with low traits.

So, clearly answering the question ‘do symptoms of schizophrenia make people more likely to commit violent crime’ is not a simple one to answer. There are many other factors to consider that make the risk higher. Added to this, there are few high-quality studies that control the effects of all of these confounding factors to assess the contribution that symptoms have to schizophrenia. Nevertheless, the literature generally shows that even after controlling for these factors, those with schizophrenia do have an increased risk for violent crime compared to the general population. However, the driving force behind violence in schizophrenia generally is arguably not mainly symptomatology. It is true that there are violent offenders who have committed a crime in direct response to their experience of symptoms, but these appear to be a minority. It is important to consider what other factors influence crime and not see a whole population of individuals who live with schizophrenia as inherently violent. Whilst media might have us believe those with schizophrenia are the most dangerous population on the planet, in reality they are a subgroup of (often vulnerable) people living with a debilitating disorder that is complicated by such stigmatisation.