"Treatment halves violent crime"

Professor Paul Lichtenstein at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet and his research group have studied over 82,000 Swedes with a psychiatric diagnosis, their medication and whether they were convicted of violent crime between 2006 and 2009. He can prove that treatment with anti-psychotic drugs and mood stabilizers reduce the risk of violent crime.

Professor Paul Lichtenstein. Photo: Ulf Sirborn

Text: Fredrik Hedlund, first published in Medicinsk Vetenskap no 3, 2014.

Are mentally ill people more violent than other people?

"Yes, people diagnosed as schizophrenic are three to four times more likely to be convicted of violent crimes. Even those with bipolar disorder have an increased risk."

How does treatment affect violent crimes?

"When diagnosed schizophrenics were given anti-psychotic drugs, violent crime was reduced by almost 50%. Almost the same reduction was achieved with mood stabilizing drugs."

That is quite a lot, isn't it?

"It is a huge amount. If you could reduce crime by 50% through political means, the achievement would be considered as very large."

What does this tell us about violent crimes committed by mentally ill people? Could you call it an effect of inadequate treatment?

"Yes, you could perhaps say that. But a better way of putting it is perhaps that our results suggest half of the violent crimes committed by people with psychotic diseases could have been prevented with treatment.

We do not medicate to reduce crime, we medicate to alleviate psychotic diseases."

What do you think these results should lead to?

"We should probably not exaggerate the importance of this finding. It is one more thing to take into consideration before making a decision on treatment. But there are many things that need to be taken into account, such as the patients' own wishes, side-effects, whether they become overweight, what other resources are available, and so on. It is not only the tendency to crime that determines whether a patient is given treatment. We do not medicate to reduce crime, we medicate to alleviate psychotic diseases."

Facts about schizophrenia

In Sweden, there are between 30,000 and 50,000 people with schizophrenia. Each year there are approximately 2,000 people in Sweden who suffer a psychosis.

  • Approximately half of them may later be diagnosed with schizophrenia.
  • A psychosis brings about a huge change in the perception of reality, where the person affected lives in a hallucinatory world where he or she may see, hear, and smell things that do not exist, or hear voices that are not there.
  • The person may also experience having unique properties such as being able to fly, being immortal or being Jesus; they may believe they can control others' thoughts or that their own thoughts are controlled by something or someone.
  • The patient lives in a world of delusions, from which it is not possible to escape by using reason.
  • To be diagnosed as schizophrenic these delusions must continue for at least six months, but there are other criteria that also have to be met.

Anti-psychotic drugs

The treatment of schizophrenia is mainly through anti-psychotic drugs. Drugs that reduce the symptoms have one thing in common: they all block D2 receptors for the neurotransmitter dopamine in the brain's neurons. For this reason it has been concluded that schizophrenia is connected with the dopamine signalling system, but exactly how is not known.

The clinical effect is related to how hard the drug binds to these receptors, apart from clozapine (Leponex etc.) which has the best anti-psychotic effect despite weak binding. It is called atypical and its mechanism is still unknown.

Source: Book of medical products (Läkemedelsboken)