Most people with untreated schizophrenia are not dangerous. The large majority will never commit a violent act. But the risk of violence is real and measurably higher when schizophrenia goes untreated, particularly when substance use is involved. Understanding the actual numbers helps separate legitimate concern from stereotype.
What the Numbers Actually Show
A large study published in JAMA tracked over 8,000 people diagnosed with schizophrenia and compared them to matched controls from the general population. Overall, 13.2% of those with schizophrenia had at least one violent criminal offense, compared to 5.3% of the general population. That works out to roughly twice the odds of violence.
But that headline number hides a critical distinction. When researchers separated out people with schizophrenia who also had a substance abuse problem, the picture changed dramatically. Those with both schizophrenia and substance abuse had a violent offense rate of 27.6%, about four and a half times the general population rate. Those with schizophrenia alone, and no substance abuse, had a rate of 8.5%, only slightly above the 5.1% rate of their matched controls. The added risk from schizophrenia alone, without drugs or alcohol, was small.
In other words, the danger people associate with schizophrenia is largely driven by substance use, not the illness itself.
How Lack of Treatment Changes the Risk
Treatment does matter. During first-episode psychosis, roughly 11.6% of people engage in some form of violence before they ever receive care. One review found that the annual rate of homicide was 15.5 times higher among people experiencing a first psychotic episode who had not yet received treatment compared to those who had.
Antipsychotic medication reduces violent crime by about 45% compared to periods when the same person is off medication, based on a study of over 82,000 patients in Sweden. That’s a within-person comparison, meaning researchers looked at the same individuals during treated and untreated periods, which eliminates a lot of confounding factors. Even in more conservative analyses using different measures of crime, the reduction held at 22% to 29%.
So untreated schizophrenia does carry a higher risk of violence than treated schizophrenia. But “higher risk” still means the vast majority of untreated individuals are not violent.
Which Symptoms Raise Concern
Not all psychotic symptoms carry equal risk. Command hallucinations, where a person hears voices telling them to do something, are among the most concerning. Research shows that people who can identify the voice they’re hearing (believing it belongs to a specific person or entity) are more likely to comply with what it says. Compliance with less dangerous commands is common, and compliance with dangerous ones, while less frequent, is not rare enough to dismiss.
Persecutory delusions also play a role. When someone genuinely believes they are being followed, poisoned, or targeted, they may act in what they perceive as self-defense. This is especially relevant for people who are homeless or living in unstable environments where actual threats exist alongside delusional ones. Distinguishing between unprovoked violence and a frightened person reacting to what they perceive as danger is often difficult, even for clinicians.
The Bigger Risk: Being a Victim
One of the most overlooked facts in this conversation is that people with schizophrenia are far more likely to be victims of violence than perpetrators. The rate of victimization is up to 14 times the rate of being arrested for a violent act. People experiencing psychosis are vulnerable to exploitation, assault, and abuse, particularly when they are homeless, isolated, or visibly disoriented. Despite this, the vast majority of published research since the 1990s has focused on whether people with schizophrenia are dangerous rather than on protecting them from harm.
What Actually Drives the Violence Risk
The factors that most increase violence risk in people with schizophrenia are the same ones that increase violence risk in anyone: substance abuse, poverty, homelessness, being young and male, and belonging to a marginalized group with limited access to healthcare. These social conditions are heavily overrepresented among people with schizophrenia, and most studies fail to fully account for them. When researchers do control for substance use and socioeconomic factors, the gap between people with schizophrenia and the general population narrows considerably.
There’s also a perception problem that compounds itself. People with schizophrenia, especially those who are homeless or behaving unusually, are more likely to be perceived as threatening by police and bystanders. This leads to more confrontational encounters, more arrests, and more entries into the forensic system, all of which inflate the apparent link between schizophrenia and violence. Public perception surveys consistently show a strong stereotype of dangerousness associated with mental illness, alongside a desire for social distance from affected individuals.
Putting the Risk in Perspective
The honest answer is that untreated schizophrenia does carry a moderately elevated risk of violence compared to both treated schizophrenia and the general population. That risk is real, and it’s one of many reasons early treatment matters. But the risk is far smaller than most people assume, heavily concentrated among those who also use drugs or alcohol, and shaped by the same poverty and instability that drive violence across all populations. About 87% of people with schizophrenia, even looking at the overall group without separating out substance use, never commit a violent offense at all. The stereotype of the dangerous “schizophrenic” does not match the data, and it causes measurable harm to millions of people who are far more likely to need protection than to pose a threat.