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Briefing Paper

April 2007

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Anosognosia as a cause of violent behavior in individuals with severe psychiatric disorders

SUMMARY: Anosognosia, unawareness of illness, is the most important reason individuals with severe psychiatric disorders do not take medication for their illness. Multiple studies have demonstrated that the presence of anosognosia increases the incidence of violent behavior, both because it is associated with medication nonadherence and because it appears to directly increase violent behavior.

Anosognosia is a major contributor to aggressive and violent behavior among individuals with severe psychiatric disorders. Because anosognosia is the major cause of medication nonadherence, the association can be assessed either by studying violent behavior and nonadherence or by studying violent behavior and measures of insight. 

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1.  Violent behavior and nonadherence

Many studies have been published linking aggressive and violent behavior to medication nonadherence. Following are three examples.

• In the United States (Massachusetts), 133 outpatients with schizophrenia were assessed for violent behavior over six months. During that period, “13 percent of the study group were characteristically violent,” and this was associated with medication nonadherence. “Seventy-one percent of the violent patients had problems with medication compliance, compared with only 17 percent of those without hostile behaviors.”

              Bartels SJ, Drake RE, Wallach MA, et al. Characteristic hostility in schizophrenic patients. Schizophrenia Bulletin 17:163–171, 1991.

• In the United States (multisite study), 1,906 individuals with schizophrenia and related disorders were prospectively followed and assessed for three years. Medication nonadherence was significantly associated with being violent, arrested, and victimized (all significant at a level of p<0.001).

Ascher-Svanum H, Faries DE, Zhu B, et al. Medication adherence and long-term functional outcomes in the treatment of schizophrenia in usual care. Journal of Clinical Psychiatry 67:453–460, 2006

• In the United States (five sites), 1,011 outpatients with severe psychiatric disorders were assessed for medication adherence and physically assaultive behavior over six months. Those who became physically assaultive were significantly more likely to have treatment nonadherence (p<0.001), to be sicker, to be a substance abuser, and to have a personality disorder.

Elbogen EB, Van Dorn RA, Swanson JW, et al. Treatment engagement and violence risk in mental disorders. British Journal of Psychiatry 189:354–360, 2006.

2.  Violent behavior and poor insight

• In the United States (North Carolina), 331 “severely mentally ill” individuals who had been involuntarily admitted to a psychiatric disorder were assessed for their history of assaultive and violent behavior. The findings indicated “that substance abuse problems, medication noncompliance, and low insight into illness operate together to increase violence risk.”

Swartz MS, Swanson JW, Hiday VA, et al. Violence and severe mental illness: the effects of substance abuse and nonadherence to medication. American Journal of Psychiatry 155:226–231, 1998.

• In Spain, 63 individuals with a diagnosis of schizophrenia or schizoaffective disorder were assessed for violent behavior during their brief hospitalizations. The strongest predictors of violent behavior were insight into symptoms (especially delusions), being sicker, and past history of violence.

Arango C, Calcedo Barba A, González-Salvador T, et al. Violence in inpatients with schizophrenia: a prospective study. Schizophrenia Bulletin 25:493–503, 1999.

• In Sweden, 40 “mentally disordered” individuals with a history of “violent criminality” were discharged from two forensic hospitals and followed for between 3 and 12 years. Twenty-two of them committed additional violent crimes, and 18 did not. Among the strongest predictors of those who committed additional violent crimes were lack of insight and “noncompliance with remediation attempts.”

Strand S, Belfrage H, Fransson G, et al. Clinical and risk management factors in risk prediction of mentally disordered offenders—more important than historical data? Legal and Criminological Psychology 4:67–76, 1999.

• In England, 503 patients in two forensic psychiatric hospitals were assessed for aggressive and violent behavior. Lack of insight strongly correlated with higher levels of such behavior.

Woods P, Reed V, Collins M. The relationship between risk and insight in a high-security forensic setting. Journal of Psychiatric and Mental Health Nursing 10:510–517, 2003.

• In the United States (Ohio), 115 individuals with schizophrenia who had committed violent acts for which legal charges were incurred were compared to 111 individuals with schizophrenia who had no history of violent acts. The violent individuals had “marked deficits in insight” and were much more symptomatic. Compared to the nonviolent individuals, those who had been violent scored significantly lower (p<0.001) on awareness of mental disorder, awareness of achieved effect of medications, and awareness of social consequences of mental disorders.

Buckley PF, Hrouda DR, Friedman L, et al. Insight and its relationship to violent behavior in patients with schizophrenia. American Journal of Psychiatry 161:1712–1714, 2004.

• In England, 44 male inpatients in a forensic psychiatric hospital were assessed for violent behavior. It was found that “a previous diagnosis of mental illness, lack of insight, and active signs of mental illness were the most predictive of inpatient violence.”

Grevatt M, Thomas-Peter B, Hughes G. Violence, mental disorder and risk assessment: can structured clinical assessments predict the short-term risk of inpatient violence? Journal of Forensic Psychiatry and Psychology 15:278–292, 2004.

• In Ireland, 157 individuals with first-episode psychosis were assessed for violent behavior. The strongest predictors of violent behavior in the week following admission was poor insight (odds ratio 2.97) and a past history of violence (odds ratio 3.82).

Foley SR, Kelly BD, Clarke M, et al. Incidence and clinical correlates of aggression and violence at presentation in patients with first episode psychosis. Schizophrenia Research 72:161–168, 2005.

• In the United States (New York), 60 male patients with psychosis who had been charged with a violent crime were assessed. Severity of community violence was strongly associated with poor insight, medication nonadherence, and substance abuse.

Alia-Klein N, O’Rourke TM, Goldstein RZ et al. Insight into illness and adherence to psychotropic medications are separately associated with violence severity in a forensic sample. Aggressive Behavior 33:86–96, 2007.

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