Which disorder is most strongly linked to aggressive and violent behavior

That being said, a small number of individuals with serious mental illnesses commit acts of violence. Individuals who are not being treated commit almost all of these acts; many of them also abusing alcohol or drugs.

THE ASSOCIATION BETWEEN SERIOUS MENTAL ILLNESS AND ACTS OF VIOLENCE

• In 2015, Swanson and colleagues published a summary of studies on serious mental illness and violent behavior. They reported:
  
  At least 20 studies have examined violence in patients with schizophrenia spectrum disorders in various clinical and community settings. A meta-analysis of this literature founded a reported risk of violence that was, on average, 3 to 5 times greater for men with schizophrenia, and 4 to 13 times greater for women with schizophrenia, compared with their counterparts without schizophrenia in the general population. The risk factor was higher for homicide as the violence outcome and for any violence when comparing patients with first-episode psychosis to population controls. The overall risk increase for violence was similar in bipolar disorder, where a recent meta-analysis synthesized nine studies and reported increased odd of violent outcomes in bipolar patients in the range of 3:1 to 6:1 compared with the general population.
• A 2014 study by Fazel and colleagues examined 24,297 patients with schizophrenia and related psychoses in Sweden over 38 years (discharged from hospitals between 1972 and 2009). Within five years of first being diagnosed, 10.7% of men and 2.7% of women had been convicted of a violent offense (i.e., homicide, attempted homicide, assault, robbery, arson, any sexual offense or illegal threats or intimidation). The rate of violent offense by the patients with psychotic disorders was 4.8 times higher than among their siblings and 6.6 times higher than among matched controls in the general population. Most strikingly, over the 38 years, the incidence of violent behavior increased in direct proportion to the decrease in hospitalization time (i.e., “fewer annual inpatient nights were associated with more violence perpetrated by those with schizophrenia and related disorders”).
• A meta-analysis of 20 studies on the relationship between schizophrenia and violence, including 18,423 patients with schizophrenia and related psychoses, reported that individuals with these diagnoses “are associated with violence and violent offending, particularly homicide,” and this was true for those with or without comorbid substance abuse.
• A meta-analysis of 204 studies of psychosis as a risk factor for violence reported that “compared with individuals with no mental disorders, people with psychosis seem to be at a substantially elevated risk for violence.” Psychosis “was significantly associated with a 49%–68% increase in the odds of violence.”
• A review of 22 studies published between 1990 and 2004 “concluded that major mental disorders, per se, especially schizophrenia, even without alcohol or drug abuse, are indeed associated with higher risks for interpersonal violence.” Major mental disorders were said to account for between 5% and 15% of community violence.
• Among 3,743 individuals with bipolar disorder, 8.4% committed violent crimes compared to 3.5% of the general population in Sweden.
• Of 8,003 individuals with schizophrenia in Sweden, 13.2% committed at least one violent crime compared with 5.3% of the general population. Concurrent abuse of alcohol or drugs accounted for much of the increased rate.
• A 2014 study in Israel identified 3,187 patients with a diagnosis of schizophrenia. They committed four times more violent crimes compared to the general population, and this difference was even more pronounced among women.
• Data on mental disorders and violence were collected on 34,653 individuals as part of the US National Epidemiologic Survey on Alcohol and Related Conditions. An analysis of the data by Elbogen and Johnson found that “the incidence of violence was higher for people with severe mental illness, but only significantly so for those with co-occurring substance abuse and/or dependence.” According to a later analysis by Van Dorn and colleagues, which was critical of the first analysis, “those with SMI [serious mental illness], irrespective of substance abuse status, were significantly more likely to be violent than those with no mental or substance use disorders.”
• A 2013 study in Australia reported that individuals with schizophrenia were four times more likely to be guilty of a violent offense compared to a matched community sample. When all individuals with comorbid substance abuse were removed from the schizophrenia sample, those without substance abuse still were more than twice as likely to be guilty of a violent offense compared to the matched community sample. The authors concluded that their study “discredits the notion that the increased prevalence of violence in schizophrenia can be solely attributed to substance abuse.”
• After reviewing the psychiatric literature from 1970 to 2007, Taylor concluded that “sound epidemiologic research has left no doubt about a significant relation between psychosis and violence, although one accounting for little of society’s violence.” The author also noted that “when violence is a problem, individuals in the immediate social circle of an individual suffering from psychosis are most at risk.”
• A study in Ohio compared 122 patients with schizophrenia who had committed violent acts with 111 patients with schizophrenia who had not committed such acts. The violent patients had significantly more prominent symptoms and significantly less awareness of their illness.
• A study of 961 young adults in New Zealand reported that individuals with schizophrenia and associated disorders were 2.5 times more likely than controls to have been violent in the past year. If the person was also a substance abuser, the incidence of violent behavior was even higher.
• A study of 63 inpatients with schizophrenia in Spain reported that the best predictors of violent behavior were being sicker (i.e., higher scores on symptom measures) and less insight into illness: "The single variable that best predicted violence was insight into psychotic symptoms."
• A 10-year follow-up of 1,056 severely mentally ill patients discharged from mental hospitals in Sweden in 1986 reported that "of those who were 40 years old or younger at the time of discharge, nearly 40% had a criminal record as compared to less than 10% of the general public." Furthermore, "the most frequently occurring crimes are violent crimes."
• A study of 331 individuals with severe mental illness in the United States reported that 17.8% "had engaged in serious violent acts that involved weapons or caused injury." The researchers also found that "substance abuse problems, medication noncompliance, and low insight into illness operate together to increase violence risk."
• In a study in Finland, an unselected birth cohort of 11,017 individuals was followed for 26 years. Men with schizophrenia without alcoholism were 3.6 times more likely to commit a violent crime than men without a psychiatric diagnosis. Men with both schizophrenia and alcoholism were 25.2 times more likely to commit a violent crime.
• Limited data are available that can be used to estimate the percentage of severely mentally ill individuals who become violent. The best study used the Danish psychiatric case register, covering the whole country, and convictions for criminal offenses. Between 1978 and 1990, 6.7% of males and 0.9% of females with "major mental disorders" (psychoses) were convicted of a violent crime ("all offenses involving interpersonal aggression or a threat thereof") compared with 1.5% of males and 0.1% of females among individuals with no psychiatric diagnosis. This analysis only used convictions; thus it can be assumed that another unknown percentage committed a violent act for which they were not charged or convicted.
• A study in Switzerland compared 282 men with schizophrenia with a matched control group in the general population. The patients were found five times more likely to have been convicted of violent crimes, mostly "assaults resulting in bodily harm." The more acutely ill the patient was, the more likely he was to have been violent.
• A study of 538 individuals with schizophrenia living in London reported the risk of conviction for assault and serious violence was 3.9 times higher in men with serious mental illness and 5.3 times in women when compared to control groups with other psychiatric diagnoses.
• A Swedish study examined the criminal records of all individuals born in Stockholm in 1953 and still living in the city 30 years later. Men and women with severe mental illness were 4.2 times (men) and 27.5 times (women) more likely to have been convicted of a violent crime compared to individuals with no psychiatric diagnosis.
• In a follow-up of patients released from a psychiatric hospital, Dr. Henry Steadman and Dr. John Monahan reported that "27% of released male and female patients report at least one violent act within a means of four months after discharge."
• In a carefully controlled study comparing individuals with severe mental illness living in the community in New York with other community residents, the former group was found to be three times more likely to commit violent acts such as weapons use or "hurting someone badly." The sicker the individual, the more likely he or she had been violent.
• In reviewing many of these studies, in 1992 Dr. John Monahan, PhD concluded:
  
  The data that have recently become available, fairly read, suggest the one conclusion I did not want to reach: Whether the measure is the prevalence of violence among the disordered or the prevalence of disorder among the violent, whether the sample is people who are selected for treatment as inmates or patients in institutions or people randomly chosen from the open community, and no matter how many social and demographic factors are statistically taken into account, there appears to be a relationship between mental disorder and violent behavior.
• A 1990 study investigated violent behavior among severely mentally ill individuals in 1,401 randomly selected families who were members of the National Alliance for the Mentally Ill (NAMI). In the preceding year, 11% of these individuals were reported to have physically harmed another person.
• The ECA surveys carried out from 1980 to 1983 reported much higher rates of violent behavior among individuals with severe mental illness living in the community compared to other community residents. For example, individuals with schizophrenia were 21 times more likely to have used a weapon in a fight.
• A Swedish study of 644 individuals with schizophrenia followed for 15 years reported they committed violent offenses at a rate four times greater than the general population.
• In reviewing early studies on discharged psychiatric patients, Dr. Judith Rabkin, PhD, concluded: "Arrest and conviction rates for the subcategory of violent crimes were found to exceed general population rates in every study in which they were measured."

VIOLENCE AND UNTREATED MENTAL ILLNESS

Most acts of violence committed by individuals with serious mental illness are carried out when they are not being treated.

Which mental health condition is most strongly associated with violent behavior?

What personality trait is most strongly linked to violence and aggression?

What personality disorders are associated with violence?

What personality disorder is aggressive?