Psychopathic traits linked to much higher risk of schizophrenia, study finds

People with high psychopathic traits face a 9.3 times higher schizophrenia risk than those with low traits, research suggests.

The study also found that individuals classified as psychopathic were 2.37 times more likely to develop the condition than their non-psychopathic peers.

Psychopathic traits are personality features involving shallow emotion, reduced empathy and limited remorse for harming others. They exist on a continuum in the population and tend to be stable over time.

Researchers combined data from people who underwent forensic psychiatric evaluations at Niuvanniemi Hospital in Finland between 1984 and 1993 with records from the Care Register for Health Care, a nationwide database of inpatient and specialised outpatient visits, diagnoses and treatments.

The team, led by Olli Vaurio, examined whether psychopathic traits are linked to a higher chance of developing schizophrenia later.

They noted neuroimaging work showing structural similarities between the brains of patients with schizophrenia and those with pronounced psychopathic traits.

In total, the study included data from 341 individuals, of whom 278 were male, with an average age of about 33.5 years.

Psychopathic traits were assessed using the Psychopathy Checklist-Revised (a standard clinical rating scale), grouping participants into low, moderate and high categories.

Results showed that, compared with participants with low psychopathic traits, those with moderate traits had a 5.3 times higher risk of being hospitalised for schizophrenia.

Twenty per cent of individuals classified as psychopathic developed schizophrenia over the follow-up period.

The researchers wrote: “The novel results suggest that there is a link between higher PCL-R scores and a higher risk of later-life schizophrenia outbreak among non-psychotic individuals undergoing FPE [forensic psychiatric evaluations].”

The study adds to understanding of links between psychopathy and schizophrenia.

However, it focused on people undergoing forensic psychiatric evaluations, which are court-ordered assessments of mental state, so the group is not representative of the wider population with mental health problems.