There is a lot of misinformation about the relationship between mental illness and violence.

Serious mental illness confers a slightly elevated risk for interpersonal violence compared to the general population, especially when serious symptoms are untreated. By serious mental illness, we are talking about any mental illness that causes serious, daily functional impairment, generally diagnoses of schizophrenia spectrum disorders, bipolar disorders, and severe depression. However, keep this in mind:

• If you control for other violence risk factors for which individuals with serious mental illness are at increased risk (substance use disorders and childhood/community violence exposure are the two biggies), then that increased risk of violence completely disappears.

• Even if serious mental illness were completely cured, the total amount of violence in the population would only drop by about 4%. And that’s total interpersonal violence, only a subset of which is gun violence committed by individuals with serious mental illness.

• People with serious mental illness are at much higher risk of being victims than perpetrators of interpersonal violence.

• People with serious mental illness are at significantly elevated risk of violence towards themselves, i.e., suicide.

One of the most confusing issues when discussing the connection between violence and mental illness is defining mental illness. Above, we use the term serious mental illness (known in the literature as SMI) to denote the most severe forms of mental illness that are often, but not always, associated with inpatient hospitalization. But what about the person who worries too much about everything and has sleep troubles and headaches because of it? Or a person with mild-to-moderate depression who can still go to work and manage their daily life? These individuals may have diagnoses like Generalized Anxiety Disorder and Major Depressive Disorder, mild or moderate, which are extremely common in the general population. When people with conditions like these seek help, it is most often voluntary and outpatient-based. People with these common, less severe forms of mental illness are not at any increased risk of interpersonal violence, though some may be at increased risk of suicide.

Another useful distinction to keep in mind is the difference between mental illness and mental distress. They are not the same thing. A person can feel mental distress because of circumstances in their life, e.g., loss of a job or difficulties in a relationship. Having mental distress doesn’t always mean that someone has a diagnosable, treatable mental illness. But distress can lead to anger and violence, whether directed toward others or to oneself. Easy access to a gun could cause mental distress to become lethal, but it doesn’t mean that the violence was caused by a mental illness or that a mental health professional could have predicted or stopped it. Furthermore, people with mental distress are highly unlikely to have been involuntarily hospitalized for a mental illness, a main criterion that might lead to someone being denied a gun purchase after a background check.

The reality is that many of the people who commit violence do not have a mental health disorder severe enough to explain their actions from that perspective.