The Relationship between Mental Disorder and Violence

Whilst some researchers appear to still be investigating the connection between mental disorder and violence, professionals including Hare (2004) have already determined that mental disorder is so convincingly linked to violence that to not evaluate the mental health of prospective employees, as part of a violence-risk assessment, is tantamount to negligence on the part of an employer (Guy, Edens, Anthony & Douglas, 2005). In 1996 and then again in 2004, Hare asserted the overwhelming importance of the link between mental disorder and violence, to the criminal justice system in the United States (Guy et al, 2005). If employers and the legal system are being warned about the propensity for violence among people with a mental disorder, what evidence do they have that a relationship exists?

‘Mental disorder’ appears to be a single term used for a huge variety of unusual or unhealthy mental functioning. At one end of the scale there is brain damage/injury and birth defects that amount to impaired cerebral function (AIC, 2002) and at the other end of the scale are conduct disorder, low self-esteem and neuroticism. Somewhere in the middle ground there appears to be psychotic behaviour, epilepsy, depression and changes in neurological function due to chemical imbalances. Wakefield (1992) suggested that a definition of mental disorder should be one that includes the words, ‘harmful dysfunction’. That is, harmful in a way that precludes the sufferer from some “socially valued benefit” (Blackburn, 1993). With such a huge term of reference for ‘mental disorder’, any number of explanations can be applied to the relationship between mental disorder and violence (AIC, 2002; Guy et al, 2005; Loeber et al, 2005; Mossman, 1995).

Violence is slightly easier to quantify. Douglas, Ogloff, Nicholls & Grant (1999) describe violence in three ways. Physical violence is a physical blow or attack on another person. Non-physical violence includes verbal abuse, threats and fear-inducing or threatening behaviour and criminal violence includes assault or harm to another person in or during a criminal action. In much of the reviewed research, violence appears to be those actions that involve threats or physical attacks.

Researchers, employers and other professionals use various methods to test individuals and gain insight into their mental state (Douglas et al, 1999; Guy et al, 2005; Mossman, 1995; AIC, 2002) Violent offenders appear to be a good source of research material and the Hare Psychopathy Checklist (Douglas et al,1999; Guy et al, 2005) and various personality tests appear to be popular methods for assessing behavioural traits. One of the first major researchers to formally assess personality/temperament and its relationship to violent behaviour, was Hans Eysenck.

To try and explain the connection between temperament, delinquency, sociopathy, and criminal behaviour, Hans Eysenck and colleagues devised the “General Arousal Theory of Criminality” (Hollin, 1992). Individuals will be extroverted, impulsive, and sensation-seeking and under conditions of relatively low stimulation they find themselves at a suboptimal level of arousal. To increase their arousal, many will participate in high-risk activities such as criminal and violent behavior (Boeree, 1998; Link & Mealey 1992; Hollin, 1992). Eysenck first postulated that sociopathy correlated with high scores on all three of the personality dimensions of the Eysenck Personality Questionnaire – extroversion, neuroticism and psychoticism. Eysenck theorized that criminality was both positively and causally related to high levels of psychoticism, extroversion and neuroticism (Holman & Quinn, 1992; Hollin, 1992; Vaughan and Hogg, 2002).

Hans Eysenck found that women tend to have higher neuroticism scores than men and men score much higher in psychoticism than do women (Hollin, 1992) and psychoticism is a likely candidate for one of the relevant gender-limited traits which fits Cloninger’s two-threshold risk model explaining the sex difference in expression of sociopathy and violence (Link & Mealey, 1992).

This supports the research findings that men are far more likely to be involved in violent crime (AIC, 2002) and that men are also known to be more aggressive than women – Wilson and Herrnstein (1985) found that men are between 5 and 50 times more likely to be arrested for violence. Even though there has been an increase in the crime rate for women in the United States since the 1960s, women still commit only about 10% of violent crimes except in the area of domestic violence (Baumeister et al, 1996). In Australia, men are about ten times more likely to be charged over a violent offence (AIC, 2002).
As Eysenck’s Personality Questionnaire is easy to administer, his theory regarding personality and criminal propensity, is easy to test (Hollin, 1992) and many psychologists have done so (Darley et al, 1991; Link & Mealey 1992; Hollin, 1992). Several other studies have used the Minnesota Multiphasic Personality Inventory (MMPI) on groups of offenders (Mossman, 1995; Baumeister et al, 1996) There are ten MMPI scales and three are relevant to low self-esteem: Depression, which includes self-deprecation; Psychasthenia, which includes anxiety and indecision; and Introversion, which includes insecurity and shyness. Wilson and Herrnstein (1985) noted that there was not a strong correlation between psychasthenia and criminality but they also noticed that both depression and introversion were negatively related to aggressive or criminal behaviour. People who are depressed, self-deprecating, insecure, and shy, make up a small portion of criminal populations (Baumeister et al, 1996).

There has been research in the past that has given the opinion that people with low self-esteem have violent and antisocial tendencies. However, Eysenck’s Neuroticism is made up of a number of factors such as anxiousness, depression, feelings of guilt, low self-esteem, tenseness, irrationality, being shy, moody, and emotional and he noted that not only do more women than men show these traits but people with these traits are less likely to become criminals or be aggressive (Link & Mealey, 1992; Hollin, 1992). Though depression is commonly viewed as a mental disorder, these studies have shown there is no link between depression and violent behaviour (AIC, 2002).
Using Wakefield’s (1992) descriptor of mental disorder, being overly egotistical or having low self-esteem could ‘preclude you from social benefit’ and thus could be termed mental disorders. Keeping that in mind, it appears that the better or stronger your ego, the more violent your actions. Gough, Wenk, and Rozynko (1965) administered the California Psychological Inventory (CPI) to young men on parole. Among the personality characteristics that predicted high criminal recidivism were being egotistical and outspoken. Being modest and unassuming were among the traits associated with men who were least likely to violate parole. These results all seem to fit the view linking an over-inflated ego to violent tendencies (Baumeister et al, 1996).

Also according to Baumeister et al (1996), another group of people known to have low self-esteem is depressed people. The United States National Research Council (1993) reported that many types of mental illness have been linked to violence, but depression had only been found in connection with family violence.

As shown here, a number of researchers have used personality inventories to determine propensity for violence. However, it has been argued by Furnham and Thompson (1991) that the findings for psychopathy reflect the type of questions asked (Hollin, 1992). Also, in 1987, Arbruthnot, Gordon & Jurkovic determined there was “no evidence of a relationship” between personality inventories and criminality (Goldsmith, Israel & Daly, 2003:72).

Mossman (1995) noted the psychological factors that increase the likelihood of violence include low intelligence, neuropsychological impairment, and mental disorder. Swanson’s 1994 ECA study suggested that serious illness, psychotic disorders, and substance abuse add to the risk of violence (Mossman, 1995). The combination of serious mental disorder and substance abuse exacerbates the risk than either problem alone.

According to Douglas et al (1999), data gathered from the MacArthur Risk Assessment Project in 1994, showed that 61% of psychiatric patients are violent in the community within 1 year of release, with 28% being seriously violent. In 1993, Lidz, Mulvey, and Gardner observed that 45% of the 714 patients in their sample were violent in the community within 6 months of release from hospital. Risk factors for violent behaviour are quite well documented and include being male, being young, prior violence, substance abuse, psychopathy, childhood abuse, evidence of psychotic symptoms, suicidal tendencies, impulsive behaviour and anger (Douglas et al, 1999).

Loeber et al (2005) found that homicide offenders were more than 2 times as likely as other violent offenders to have a conduct disorder diagnosis. However this should be interpreted with caution. According to Loeber et al (2005) many of the symptoms of conduct disorder are acting out behaviours and it is only an increase of this behaviour over time that leads to homicide.

Psychopaths constitute another relevant group on the edge of normality. Hare (1993) described them as social predators and they commit a high rate of violent crimes, possibly as many as 50%. Concerning prior criminal and violent behaviour, Hare noted that of hospitalised psychopaths, 64% had previous convictions or arrests for a criminal offence and 40% had been arrested for or convicted of violent offences. Sixty-two percent of patients had a history of physical violence against others and 26% of the patients were physically violent in the 2 weeks before admission. Approximately 1 in 5 patients had previously used a weapon (Douglas et al, 1999).

It doesn’t appear to matter how an understanding is garnered, the ramifications of developing an understanding of the causes of violent behaviour are many. Guy et al (2005) have reported that psychopathy and related terms such as ‘antisocial personality disorder’ play a major role in civil statutes in some American states with Sexually Violent Predator laws e.g., in Texas. Similarly, in the United Kingdom, psychopathy seems part of the definition of ‘dangerous and severe personality disorders’ and also is used to inform the Dangerous Offender Law in Canada. It has also been noted that psychopathic youths are more likely to be tried in the adult criminal justice system rather than to be referred to the juvenile courts (Guy et al, 2005).

The workplace is another area where predicting violent behaviour is becoming a necessity. In many workplaces, psychological testing is commonplace but acting on the results or even doing the testing in the first place, is an area of concern for employers and law makers. Mossman (1995) noted some of the difficulties facing employers. He notes that discrimination against suitably qualified potential employees, on the basis of mental or physical disability, contravenes The Americans With Disabilities Act of 1994, the Rehabilitation Act of 1973, and statutes in almost all states. There are limits on the types of medical and psychological examinations that can be administered to employees. Direct questions about disability and impairments are not permitted, but questions regarding the worker’s ability to perform are allowed.

Mossman (1995) also noted concerns about one recent legal case that has generated substantial interest from employers regarding their ability to protect themselves from liability. Apparently a California appeals court ruled that a company’s use of Psychscreen – a psychological test that combines questions from the MMPI and the California Psychological Inventory – violated an employee’s privacy.

Although they can be held liable for their employees’ violent acts, employers are limited in the way they can gain the information they need to predict violence. Mental health professionals can only estimate an individual’s risk of acting violently over a period of time but employer’s still need this information to protect themselves and other employees from potential harm (Mossman, 1995).

There are many reason employers should assist their workers in getting appropriate treatment for any mental health issues and to help employees cope with problems that their very work might generate or exacerbate. Sperry et al, 1994 give good reasons for employers to employ mental health workers to recognise and reduce potential liability for employee violence. They found that mental health consultants can help employers recognize that “mentally healthy workers are less prone to injury and illness, use fewer physical health benefits, are less prone to injury, and are more productive” (Mossman, 1995).


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