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A man who drove a car along three blocks of pavement in New York’s Times Square, killing a teenager and injuring 22 people, said he had “heard voices”, according to law enforcement sources.
Dr Shubulade Smith, Clinical Senior Lecturer, Institute of Psychiatry Psychology & Neuroscience, King’s College London, said:
Q: How common is it for people with schizophrenia to carry out violent attacks?
“Fairly uncommon, e.g. People with schizophrenia are responsible for ~5% of the violent incidents (Fazel and Grann, 2006).”
Q: How does this frequency compare to people who e.g. are drunk and carry out violent attacks?
“It’s much rarer for people with schizophrenia to behave violently than those who are drunk. Alcohol accounts for a 13-fold increase in the risk of violence towards others, compared with a 1.2-fold risk of violence towards others in schizophrenia (Hillbrand 2001, Fazel et al 2009). In the US approximately 40% of homicide offenders had been drinking around the time of the offence (Rozein 1997).”
Q: How common is it for people with schizophrenia to be victims of violent attacks?
“People with schizophrenia are much more likely to be victims of violence than perpetrators, with approximately 23-35% of people with schizophrenia/psychosis reporting violent victimisation (from 2.3 to 140.4 times general population rates of violent victimisation) (Dean et al 2007, Maniglio 2008).”
Q: What can be done for people who are hearing voices – how successful is the treatment, how early and regularly does treatment need to be given?
“There are many causes of hearing voices, these range from normal variation to clinically significant and abnormal. Schizophrenia is only one of these causes. The treatment and the need for treatment depend on the cause and clinical significance, i.e. if it interferes with a person’s ability to function. Treatment in schizophrenia consists of a combination of pharmacological, psychological and occupational therapeutic input. This needs to be done early and regularly and can provide successful resolution of voices in about 2/3- 3/4 of sufferers. In the other 25+% the voices may persist, although the treatment can help with the severity of any distress associated with the voices.”
Dr Andreas Meyer-Lindenberg, Director of the Central Institute for Mental Health in Mannheim, Chair of Psychiatry at the University of Heidelberg and Editor-in-Chief of European Neuropsychopharmacology, said:
Q: How common it is for people with schizophrenia to go on to carry out violent attacks?
“The great majority of patients with schizophrenia are never violent but the disease does carry an increased risk of violence, often through delusions and hallucinations. Since schizophrenia is relatively rare, only about 2.3% of violent crime is linked to that disorder Fazel, Seena, and Martin Grann. “The population impact of severe mental illness on violent crime.” American journal of psychiatry 163.8 (2006): 1397-1403.)”
Q: How that compares to people who e.g are drunk to carry out violent attacks?
“Only about 5% of violent attacks come from a person with any severe mental illness, so the vast majority are unrelated to mental illness (Fazel, Seena, and Martin Grann. “The population impact of severe mental illness on violent crime.” American journal of psychiatry 163.8 (2006): 1397-1403.). In contrast, alcohol consumption shows a strong relationship.
“Alcohol use is implicated in approximately 50% of all violent crimes and sexual assaults in industrialized nations. Both acute and chronic alcohol intake increase the risk for alcohol- associated aggression. (Heinz, A. J., Beck, A., Meyer-Lindenberg, A., Sterzer, P., & Heinz, A. (2011). Cognitive and neurobiological mechanisms of alcohol-related aggression. Nat Rev Neurosci, 12(7), 400-413. doi:10.1038/nrn3042)”
Q: How common it is for people with schizophrenia to be victims of violent attacks?
“This is much more common than for the general population. In a recent study over 10% of patients reported being the victim of a violent crime in a one month period (Fitzgerald, Paul B., et al. “Victimization of patients with schizophrenia and related disorders.” Australian and New Zealand Journal of Psychiatry 39.3 (2005): 169-174.)”
Q: What can be done for people who are hearing voices – how successful is the treatment, how early and regularly does treatment need to be given?
“There are effective pharmacotherapies and psychotherapies for people suffering from schizophrenia. Someone hearing voices should be evaluated by a psychiatrist since it has been shown that the effects of treatment are the better the earlier the treatment commences. About one quarter to one third of patients have only one episode of the illness in their life and the prognosis is then excellent, in the remainder it recurs or can become chronic and requires regular visits and treatments. (Kahn, R. S., Sommer, I. E., Murray, R. M., Meyer-Lindenberg, A., Weinberger, D. R., Cannon, T. D., . . . Insel, T. R. (2015). Schizophrenia. Nature Reviews Disease Primers, 15067. doi:10.1038/nrdp.2015.67).”
Prof Sir Robin Murray, Professor of Psychiatric Research, Institute of Psychiatry Psychology & Neuroscience, King’s College London, said:
Q: How common is it for people with schizophrenia to carry out violent attacks?
“People with schizophrenia are about twice as likely to carry out violent acts as the general population – but this is still a very small percentage of all those with the illness. The majority of those people with schizophrenia who are violent are those who are using alcohol or especially illicit drugs – it’s generally the case that the drug use starts before the schizophrenia and in fact causes it. This is especially true of people who use cannabis or synthetic cannabinoids like spice and K2. Relatively few non-substance using people with schizophrenia are ever violent.”
Q: How does this frequency compare to people who e.g. are drunk and carry out violent attacks?
“As noted above it’s the drug use rather than the schizophrenia that is the main driver of the violence. High potency cannabis (skunk) and synthetics are an increasing cause of violence.”
Q: How common is it for people with schizophrenia to be victims of violent attacks?
“Very much more common.”
Q: What can be done for people who are hearing voices – how successful is the treatment, how early and regularly does treatment need to be given?
“80% of people with their first episode will recover but sadly a proportion will have further episodes and 25% will go on to be chronically ill. The ones who do worst are those who continue to take drugs like amphetamines, skunk and synthetics.”
The SMC also produced a Factsheet on schizophrenia which is attached and available here: http://www.sciencemediacentre.org/schizophrenia/
Declared interests
None declared