Comorbid Substance Abuse and Mental Illness May Lead to Violent Behavior

Scientists have found that being diagnosed with mental illnesses such as bipolar disorder or schizophrenia does not necessarily make an individual more prone to violent behavior. Individuals with these psychiatric disorders who also abuse alcohol or drugs, however, do have a stronger relationship with violence, according to a new study.

Bipolar disorder causes several complicated symptoms and risk factors, including mania or hypomania, depression, anxiety, high stress, loss of concentration, and mood swings. Individuals with bipolar disorder also have a high tendency to experience coexisting disorders, such as anxiety disorders, attention-deficit hyperactivity disorder (ADHD), physical health problems, and substance abuse disorders. Although bipolar disorder patients exhibit an array of adverse health problems due to their mental illness, their propensity toward violence has remained relatively unexamined. In their latest study, researchers from University of Oxford’s Department of Psychiatry in England and the Center for Violence Prevention and the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet in Stockholm teamed up to investigate the risk of violent crime among individuals with bipolar disorder.

The research team, led by Dr. Seena Fazel, conducted a longitudinal investigation between 1973 and 2004 comparing a population of bipolar patients with the general population, as well as their unaffected siblings as a control group. For the test population, researchers included 3,743 individuals who were diagnosed with bipolar disorder, based on information from Swedish hospital discharge registers. Also, 37,429 individuals from the general population and 4,059 unaffected siblings were used as comparisons. Researchers measured the rates of violent crime—such as homicide, assault, sexual assault, robbery, arson, or illegal threats or intimidation—among all three population groups.

By the end of the study’s time frame, 314 bipolar patients (8.4%) had committed acts of violent crime, compared to 1,312 individuals from the general population (3.5%). Although the rate of violence was higher in the bipolar population than the general population, the rates of violence were comparatively equal among the two groups when the researchers adjusted to remove the influence of substance abuse. When compared to their unaffected siblings, bipolar patients without substance abuse showed an even lower rate of violence. Bipolar patients who also exhibited substance abuse comorbidity displayed the strongest relationship with risk of violence. Moreover, the rate of violence was the same among individuals with bipolar disorder or schizophrenia, and substance-abusing individuals who do not suffer from these disorders. The common denominator among the populations’ tendencies toward violence, the researchers point out, was substance abuse.

Substance abuse is a common adverse health outcome of bipolar disorder and schizophrenia. Approximately 20% of bipolar patients and 25% of schizophrenic patients are believed to have comorbid substance abuse disorders. Bipolar and schizophrenic individuals may sometimes resort to self-medication through alcohol and illicit drugs as a way to manage or alleviate their symptoms and side effects. Because of the high prevalence of substance abuse among this population, it also has a higher rate of violence than the general public (whose rate of substance abuse is around 2% of the population).

Schizophrenia and bipolar disorder are commonly stereotyped as mental illnesses that incite violence or aggression. However, the researchers suggest that these mental illnesses alone do not cause individuals to act more violently, but the coexistence of these psychiatric disorders and substance abuse does. The general public assumption regarding these illnesses and violence, researchers state, is quite inaccurate. As a result, rather nonviolent psychiatric patients in England and Sweden have been erroneously placed under secure hospitalization in recent years, based on the fear that they pose a possible threat to society. Because of this misperception, many individuals suffering from these serious disorders may feel stigmatized and therefore are reluctant to seek treatment. Nonetheless, those who do receive professional treatment, including psychotherapy and/or pharmacological therapy, are able to cope with their disorders throughout everyday life and improve their general health. Recovery is also attenuated by strong and persistent familial support.

Although current diagnostic practices for bipolar disorder do not require practitioners to perform standard risk assessments for violence, the researchers recommend that doctors consider this practice with bipolar patients who also exhibit substance abuse disorders. Their study is available in the current issue of Archives of General Psychiatry.

Source: Reuters Health, Kate Kelland, Mental Illness Alone Not Linked to Violence, September 6, 2010

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