Schizophrenia and Violence: What the Data Show

In a Swedish national cohort of 24,297 patients with schizophrenia and related disorders, 10.7% of men and 2.7% of women were convicted of a violent offense within 5 years of their first diagnosis.¹ Over a 35-year period, register-based studies put the absolute risk of violence perpetration at less than 1 in 4 for men with schizophrenia spectrum disorders and less than 1 in 20 for women.²

Relative to people without these disorders, the pooled odds ratio for violence perpetration was 4.5 in men and 10.2 in women in a 2022 meta-analysis.² The odds ratio was higher in women while the absolute risk was lower. Much of the excess is concentrated in people who also have a substance use problem.^{3, 4}

The excess risk is concentrated in people with substance misuse

A Swedish register study compared 8,003 patients diagnosed with schizophrenia with 80,025 general population controls. Only offenses after the second inpatient diagnosis were counted, in registers running from 1973 through 2004. Violent crime meant any conviction for homicide, assault, robbery, arson, a sexual offense, illegal threats, or intimidation.³

Source: Fazel et al., 2009.³

Among those with substance abuse comorbidity, 28.3% of patients had a violent offense compared with 17.9% of their unaffected siblings, an adjusted odds ratio of 1.8, which the authors read as familial confounding.³

A 2009 meta-analysis of 20 studies and 18,423 people with schizophrenia and other psychoses found the same pattern: an odds ratio of 2.1 without substance abuse comorbidity and 8.9 with it. Risk estimates in people with substance abuse and no psychosis were similar to those in people with psychosis and substance abuse.⁴ The review's homicide studies, pooled with no time period stated, put the risk of committing homicide at 0.3% in people with schizophrenia and 0.02% in the general population; the authors called the individual risk "very small."⁴

Violence in first-episode psychosis, by severity

A meta-analysis of 9 studies pooled the proportion of patients with first-episode psychosis who had committed violence. It was 34.5% for any violence, 16.6% for serious violence, and 0.6% for severe violence.⁵ The authors' conclusion places this violence before presentation for treatment and describes severe violence resulting in serious or permanent injury as uncommon.

Serious violence was associated with a forensic history (odds ratio 4.42), the duration of untreated psychosis (2.76), and total symptom scores (2.05).⁵

Are people with schizophrenia more likely to be victims?

A meta-analysis of adults with a psychotic disorder reported a median prevalence of 20% for violent victimization, and victimization rates approximately 4 to 6 times higher than in the general community. Depending on the period examined, 1 in 5 (3 years or less) or 1 in 3 (all of adulthood) had been the victim of a crime.⁶ In a Chicago sample of 936 adults with severe mental illness, a broader group than schizophrenia, interviewed with the National Crime Victimization Survey, more than one quarter had been victims of a violent crime in the past year.⁷

The statement that people with a psychotic disorder are "more often victim than perpetrator of violence" appears in the 2019 meta-analysis as a description of earlier studies.⁶ A 2020 Swedish register study complicates it: across all psychiatric disorders, the unadjusted rates were 7.1 per 1,000 person-years for being subjected to violence and 7.5 for perpetrating it, compared with 1.0 and 0.7 in matched people without psychiatric disorders. In the adjusted models, schizophrenia was the one diagnosis not associated with subjection to violence, a result the authors reported after accounting for comorbid substance use and personality disorders.⁸

The meta-analysis and the Chicago study measured crime victimization. The register study defined subjection to violence as an outpatient visit (excluding primary care), inpatient episode, or death associated with an injury purposefully inflicted by another person.⁸

Risk factors for violence in psychosis

A review of 110 studies covering 45,533 people with psychosis separated dynamic, or modifiable, risk factors from static ones.⁹

• Modifiable: hostile behavior, recent drug misuse, recent alcohol misuse, poor impulse control, and non-adherence with psychological therapies and with medication
• By domain: criminal history factors had the strongest association with violence (odds ratio 3.1), followed by substance misuse (2.3)
• Other associations: a history of being violently victimized (odds ratio 6.1) and recent homelessness (2.3)

In the Swedish cohort, three risk factors present before diagnosis predicted any adverse outcome, meaning a violent conviction or premature death: drug use disorders, criminality, and self-harm. The same three were risk factors in unaffected siblings and in the general population.¹

Antipsychotic treatment is associated with fewer violent convictions

A Swedish register study followed all 82,647 people prescribed antipsychotics or mood stabilizers from 2006 to 2009, whatever the diagnosis. Of the men, 6.5% were convicted of a violent crime during the study period, and of the women, 1.4%.¹⁰

The study compared each person's periods on medication with the same person's periods off it. Across the whole cohort, the hazard ratio for violent crime during antipsychotic treatment was 0.55 (95% CI, 0.47 to 0.64). Among the 9,125 people with schizophrenia it was 0.65 (0.45 to 0.93).¹⁰ Clozapine was coded separately, and the authors stated that the analyses were underpowered to investigate it.¹⁰

The authors wrote that within-individual studies "cannot prove causality because other time-varying factors could be associated with adherence to treatment." For depot medication, across the whole cohort, the hazard ratio was 0.60.¹⁰ I've written separately about long-acting injectable antipsychotics.

In a 12-week randomized trial of physically assaultive inpatients with schizophrenia or schizoaffective disorder, clozapine was superior to olanzapine and haloperidol in reducing the number and severity of physical assaults.¹¹ Decisions about medication are made with the prescriber.

If someone is at immediate risk of harming themselves or others, that's an emergency.

Limitations of the evidence

This evidence has limitations. First, the absolute figures are Swedish conviction data, which undercount violence that never reaches a court and may not transfer to other countries. Second, the medication findings are observational and can't establish that treatment caused the difference. Nevertheless, the pattern is consistent across registers and meta-analyses: the absolute risk is highest in men and in people with substance misuse.

These are group figures, and a diagnosis alone can't say what one person will do. Substance misuse and non-adherence are modifiable factors that a treatment plan can address.

In a crisis: call or text 988, or go to the nearest emergency department. A first episode of psychosis belongs in a hospital-based or coordinated specialty care program.

I start and manage clozapine in an outpatient practice in Chelsea, Manhattan. Details are on the schizophrenia care in NYC page. Clozapine should not be stopped, skipped, or restarted without the prescriber. This page is general information and does not replace an evaluation.

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