Why the Mentally Ill are Not Dangerous

mentally ill dangerousAlthough America’s history is ripe with shooting sprees, in the past decade we have seen what seem like random shooting sprees across the nation, in schools, malls and movie theaters. The media is quick to report such violence, as it makes waves. Regardless of how deadly or scary these killings are, Americans want to hear and read about them in newspapers, magazines and on television. Often, after the initial news, further updates will emerge that show the shooter had left signs prior to the shooting. These signs generally emerge from letters, diaries, e-mail, and most frequently social media. And most frequently, these signs lead the public to believe that the shooter was struggling with mental illness.


These events and the accompanying media coverage have probably fed the public’s perception that the mentally ill are violent and dangerous. Scientific American reported in 2011 that 60-80 percent of the population believes that the mentally ill, especially the severely mentally ill such as those with schizophrenia, are dangerous and likely to commit violent acts. However, when closely examining research on the subject it appears that these disorders are not actually good predictors of dangerous or aggressive behavior.

After all, 50% of the population is likely to experience a diagnosable mental illness within their lifetime. Even when we examine the severely mentally ill, the numbers do not correlate. Although over 1% of the population has schizophrenia, the severely mentally ill account for only three to five percent of violent crimes within the population. Data indicates that other behaviors and factors are likely to be better predictors of aggressive behavior.


Even within the general population it is understood that not all psychological disorders foretell violence. Common mental disorders such as depressive disorders, anxiety disorders, and eating disorders seem to be excluded from the public’s belief about violence in the mentally ill. Indeed, it is commonly understood that violence within this population is usually focused inward and results in self-harm or suicide. However, such disorders as schizophrenia, bipolar disorder or psychotic depression are believed to be dangerous conditions. Symptoms of schizophrenia include delusions and hallucinations, disturbance and disorganization in thoughts. Bipolar disorder is characterized by alternating periods of depression and mania. Mania involves a boost in energy, reduced need for sleep as well as symptoms of euphoria and grandiosity. Psychotic depression includes acute depressive symptoms as well as delusions and/or hallucinations.


Some research has indicated that there is a small association between violence and severe mental disorder such as the ones described above. However, the correlation is much smaller than the public seems to believe and does not mean that the disorders themselves cause violence. Scientists argue that the correlation may actually be in the other direction; chronic aggression may create stress triggering mental illness in those that are predisposed to it. Scientists are now trying to pinpoint other confounding factors in this correlation, and many signs point to drug and alcohol abuse. In a 1998 study, researchers found that almost a third of severely mentally ill patients with substance abuse problems engaged in violent acts within a year of leaving critical hospital care. Alternately, for those severely mentally ill without substance abuse problems less than one fifth committed violent acts.


Substance abuse seems to be a better predictor of violent behavior overall than mental illness, even when it is severe. Furthermore, proper treatment of mental illness can effectively eliminate the risk of violent behavior due to mental disorder. Research has shown that there is no difference between the prevalence of violence between the severely mentally ill who were medicated and the mentally healthy people.


The stereotype of the crazed individual killing strangers in public simply does not hold up to the research. Although some tragedies of this type definitely exist, these instances are quite rare. Debunking this misconception is a good first step in normalizing severe mental illness and getting these individuals the help they need before tragedy occurs.