Mental Illness and Crime

Mental illness involves a variety of mental health conditions such as disorders that affect one’s thinking, moods and behaviour around other people or even when alone. It exists in various forms: anxiety disorder, bipolar disorder, psychotic disorder, mood disorder, eating disorder and dementias. They are characterised by the following signs and symptoms: social withdrawal and isolation, a change in personality, especially if a person is acting differently from the way they usually are, and unpredictable anxiety and anger, very high or low moods, suicidal thinking and a sense of hopelessness in life. Metzl and MacLeish (2015) explain that either biological or environmental factors can cause a mental illness. Biological factors include inherited traits; studies show that it is more common in individuals whose blood relatives had the condition. Brain chemistry is also a biological factor, if neurotransmitters and the neural network system are impaired. It causes change in the functions of the nerve receptors, hence resulting in depression.

Crime is usually associated with a person’s behaviour, and the behavioural patterns can be used in forensics to determine the true suspect in a crime. Just as by the definition of WHO, it is the intentional use of physical force either to threaten or cause injury and harm to oneself or others. Some of the criminal activities involve robbery, domestic violence, rape, and murder. According to 2014 report by Law and Human Behaviour, there is a high number of people with mental illness in prison although no predictable patterns are linking mental illness to crime (Lorenc et al., 2012).

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There is a rise in the number of youths with mental illness, and it may be associated with hard living conditions and the increase in drug abuse rates among the youths. According to WHO, one in every five American has mental illness. The number among prisoners is also very high, over 60% and 40% of both female and male prisoners respectively have a mental illness, totalling to more than 1.2 million people (Hiday & Moloney, 2014). The high numbers thus invoke debates on whether there is a relationship between mental illness and crime. Stressful life experiences play a bigger role in causing mental illness, especially losing a loved one through murder or divorce, losing a job, and being diagnosed with deadly diseases such as cancer. Some people do not have the power to overcome such experiences; therefore, they gradually develop depression and later mental illness. There is no proven fact that all mental disorders lead to criminal activities because there is some case of normal healthy people developing mental disorders after realising what they have done. Therefore, when measuring the relationship between mental illness and crime, the nature of aggression should also be considered.

According to the research by Lorenc et al. (2012), analysis by the National Epidemiologic Survey on Alcohol and Related Conditions has proven thatMental Illness mental illness and violence are primarily related and influenced by growth of risk factors such as historical factors (physical abuse and past violence), clinical factors (substance abuse and severe disease diagnosis), and contextual factors (victimisation, unemployment and divorce). It showed little violence relationship to those who had mental disorder, but no substance abuse. Patients with psychotic disorders such as schizophrenia, mania, and organic brain syndrome were also diagnosed and were found to behave violently contributing to 10% of the criminal activities. However, the numbers still do not contribute to the 90% of violence occurring in the general population without mental illness.

The risks factors are statistically used to predict violence in people both with or without mental illness and hence cannot be associated only to those with a mental disorder as per the public perception. Therefore, mental health professionals use the associated risks factors as predictors of violent behaviours. Addiction to drugs also causes mental illness and criminal aids activities, therefore, linking the two together. Most of the studies show that violent behaviours are high from patients with bipolar disorder who also has substance and alcohol abuse. Hence, substance abuse among mentally disordered can be used to predict violence in a community. Even though some may not be involved in criminal activities, substance and alcohol abuse increases the risks of criminal victimisation to those with a mental disorder. The association between mental illness and violence can, therefore, be reduced if drug and alcohol abuse is taken into consideration and eliminated (Van Dorn et al., 2012).

Public perception always associates mental illness with criminal conducts. As a result, there is a lot of stigmatisation that the two are inseparable, and it may be because of the symptoms of mental illness such as anxiety, anger and social withdrawal. These perceptions have been further promoted by the media reporting violent crimes committed by those with mental illness, especially the recent mass shootings in schools and the streets (Metzl & MacLeish, 2015). They tend to focus on the mental illness and publicise it, forgetting that most of the violent crimes in the society are committed with people with no mental disorder. Therefore, such societal biases enhance the stigma faced by mental health victims. It also leads to discrimination and fear of seeking treatment, hence escalating the problem further. The prejudices have also contributed to the heated discussions on coerced treatment methods for those with severe mental illness. These kinds of arguments only rekindle anger in the victims, making them hate the society.

In conclusion, although there is a high number of prisoners with mental illness, which does not necessarily link mental illness as a key contributor to crime. Just as Hiday and Moloney (2014) illustrate, the majority of the prisoners develop mental illness after being convicted due to the harsh conditions inside the jails, ranging from lack of freedom, poor meals, and bullying from their fellow inmates. Some also develop mental disorders as a result of the guilt of committing a crime, which eliminates the belief that mental illness leads to high crime rates. According to the observations on the various studies, it is only in a few cases that mental illness is a direct cause for violence. In most cases, other factors, especially substance and alcohol abuse, were the main contributors to crime in people with mental disorders. Stigmatisation and victimisation from the public are among the causes of crime among the mentally disordered. Individuals with mental health issues tend to feel like outcasts, therefore, making them develop a negative attitude towards people, especially those who look down upon them. Just a slight provocation can result in violent reactions from such people. Thus, it is of great importance to raise awareness on mental illness and eradicate stigmatisation and the public perception about its relationship with crime, so that a large number of mental health victims can seek help before their condition deteriorates.



Hiday, V. A., & Moloney, M. E. (2014). Mental illness and the criminal justice system. In The Wiley Blackwell encyclopedia of health, illness, behaviour, and society (pp. 1-5). Wiley.

Lorenc, T., Clayton, S., Neary, D., Whitehead, M., Petticrew, M., Thomson, H., Cummins, S., Sowden, A., & Renton, A. (2012). Crime, fear of crime, environment, and mental health and wellbeing: mapping review of theories and causal pathways. Health & Place, 18(4), 757-765.

Metzl, J. M., & MacLeish, K. T. (2015). Mental illness, mass shootings, and the politics of American firearms. American Journal of Public Health, 105(2), 240-249.

Van Dorn, R., Volavka, J., & Johnson, N. (2012). Mental disorder and violence: Is there a relationship beyond substance use? Social Psychiatry and Psychiatric Epidemiology, 47(3), 487-503.