Wellcome researcher Professor Seena Fazel and his team at the University of Oxford studied data from more than 2.8 million people. Their sample included people with schizophrenia and bipolar disorders and people without any psychiatric illnesses.
They looked at whether violent crime occurred in the days after six trigger events:
losing a parent
exposure to violence
traumatic brain injury
All the events were associated with an increased risk of violent crime in the week after exposure. This was true whether people had psychiatric disorders or not.
Exposure to violence seemed to have the biggest effect.
People diagnosed with schizophrenia and bipolar disorders have higher rates of criminal convictions than the general population, but there's little evidence of the triggers for violence. Understanding these triggers could help improve risk assessments.