Antipsychotic medication can halve violent crimes among people with psychiatric illnesses, according to research.

Psychiatric patients were 45 per cent less likely to be convicted of a violent crime when they were on medications such as clozapine or risperidone, a report by a team of UK and Swedish researchers published in The Lancet yesterday (May 8), has found.

The report, which looked at more than 80,000 people with psychiatric diagnoses in Sweden between 2006 and 2009, also found that mood stabilisers cut rates of violent crime among patients with bipolar disorder by 24 per cent.

However, the team said it found no evidence that combining mood stabilisers and antipsychotic drugs had any further effect on reducing the risk of violence.

Psychiatric patients were 45 per cent less likely to be convicted of a violent crime when on medications such as risperidone, researchers have found	More on mental health Update: Understanding schizophrenia Update: Managing psychosis 'Bizarre' that pharmacy does not have a bigger role in tackling mental illness, says NHS Alliance chief
	Antipsychotic and mood-stabilising medications are most commonly used to treat schizophrenia, bipolar disorder and related disorders, which affect up to 2 per cent of the population, the research team said. However, many people in the study were prescribed the drugs for disorders such as depression or alcohol and drug misuse, it said.

Although there was already "clear evidence" these medications reduced the risk of relapse and re-hospitalisation, there had previously been very little evidence of their effects on some "adverse outcomes", such as violent behaviour, it said.

The study provided evidence that violence was "to a large extent preventable" in patients with psychiatric disorders, said Seena Fazel, senior research fellow at Oxford university's department of psychiatry, who led the research.

Clinical guidelines in the UK recommend patients with schizophrenia are assessed for the risk of violence and the research team suggested that healthcare professionals should take their findings into account when considering treatment options for patients with psychiatric disorders.

Antipsychotic prescriptions in the UK rose by 82 per cent between 1998 and 2010, according to a 2012 study quoted by the research team. Patients with schizophrenia and related psychoses are four times more likely to act violently against others, the team said.

	Should 'knock-on' benefits such as reduction in violent crime be something Nice should consider when making a decision to approve a medicine?   We want to hear your views, but please express them in the spirit of a constructive, professional debate. For more information about what this means, please click here to see our community principles and information