Introduction
Understanding the motivations behind criminal acts is a fundamental challenge for the criminal justice system. The fields of criminal psychology and criminal psychiatry offer distinct but complementary perspectives on this issue. Criminal psychology seeks to explain the thoughts, intentions, and reactions of offenders, exploring why individuals engage in criminal behaviour. Criminal psychiatry, a medical specialism, focuses on the diagnosis and treatment of mental disorders in the context of criminal law. This essay will first explore some key psychological theories concerning the mind of a person committing a crime. It will then examine how the legal system in England and Wales, with the input of psychiatry, responds to offenders who experience mental health issues, considering the defences available and the sentencing options that aim to balance punishment with care.
Psychological Explanations of Criminal Behaviour
Criminal psychology provides various theoretical frameworks to understand the "criminal mind." These theories move beyond a purely legalistic view of crime as a simple choice, suggesting that behaviour is influenced by a range of internal and external factors.
One major area is learning theory, which posits that criminal behaviour is learned in the same way as any other behaviour. For example, Edwin Sutherland's theory of differential association suggests that individuals learn criminal values, attitudes, and techniques through interaction with others, particularly in close personal groups (Sutherland and Cressey, 1974). If an individual is exposed more to pro-criminal attitudes than to anti-criminal ones, they are more likely to offend. This perspective implies that the "criminal mind" is not inherently different, but rather has been shaped by its social environment.
Cognitive theories focus on internal thought processes. Proponents argue that offenders often display faulty or biased thinking patterns. Yochelson and Samenow (1976), in their study of offenders, identified various "cognitive distortions," such as rationalising criminal behaviour, blaming others for their actions, and minimising the harm they cause. From this perspective, an offender's actions are driven by a distorted perception of reality that allows them to justify their conduct. Cognitive Behavioural Therapy (CBT), a common intervention for offenders, is based on this approach and aims to correct these thinking patterns to reduce reoffending.
Another well-known theory is Hans Eysenck’s personality theory, which proposed a biological basis for criminal tendencies (Eysenck, 1977). He argued that certain personality traits—extraversion, neuroticism, and psychoticism—were linked to a higher likelihood of offending. Individuals high in these traits, he suggested, have a nervous system that is harder to socialise and condition, making them more impulsive and less responsive to the aversive consequences of punishment. While these psychological theories offer valuable insights, they provide explanations rather than legal excuses. The criminal law must translate these complex issues into a framework of legal responsibility.
The Legal Framework for Mental Health in Criminal Law
The law of England and Wales does not excuse criminal conduct simply because a psychological theory might explain it. However, it does recognise that a person's mental state can be so severely affected that it impacts their legal culpability. This is where criminal psychiatry plays a vital role, providing expert evidence to the courts on an offender’s mental condition.
The most famous legal test for insanity is the M’Naghten rules, which originated in the nineteenth century (M'Naghten's Case (1843) 8 ER 718). To succeed with an insanity defence, the defence must prove that at the time of the act, the defendant was labouring under a "defect of reason, from a disease of the mind," such that they did not know the nature and quality of the act they were doing, or, if they did know it, they did not know it was wrong. These rules are widely criticised as being medically and legally outdated. The term "disease of the mind" is a legal, not a medical, concept, and the focus on cognitive understanding (knowing the act was wrong) fails to account for conditions where an individual knows their act is wrong but has no ability to control their impulses. Consequently, the insanity defence is rarely used.
A more modern and frequently used partial defence is that of diminished responsibility, which is only available for the crime of murder. If successful, it reduces the conviction to manslaughter. The defence was updated by section 52 of the Coroners and Justice Act 2009, which amended the Homicide Act 1957. A defendant must show that they were suffering from an "abnormality of mental functioning" which (a) arose from a recognised medical condition, (b) substantially impaired their ability to understand their conduct, form a rational judgment, or exercise self-control, and (c) provides an explanation for their acts or omissions in the killing. This modernised framework requires psychiatric evidence to establish a "recognised medical condition," linking the legal test directly to current psychiatric understanding, unlike the archaic M'Naghten rules.
Psychiatric Care for Offenders
The question of how to deal with offenders who have mental health issues lies at the heart of the intersection between law and psychiatry. The criminal justice system is tasked with both punishing wrongdoing and protecting the public, but there is a growing recognition that for many offenders, treatment is a more appropriate and effective response than punishment alone.
The prison population in England and Wales has a disproportionately high rate of mental illness. The Bradley Report (2009) highlighted this issue, finding that the criminal justice system had become a default provider for many people with mental health problems who should have been dealt with by the health and social care systems. It recommended diverting individuals out of the justice system and into treatment services where appropriate. This approach recognises that imprisoning a seriously ill person can worsen their condition and may not address the underlying causes of their offending, thereby failing to reduce the risk of reoffending upon release.
When an offender is found to have a mental disorder, the courts have several sentencing options under the Mental Health Act 1983 (MHA 1983). A judge can issue a hospital order (s.37 MHA 1983), which detains the offender in a psychiatric hospital for treatment instead of sending them to prison. For more serious offences, this can be combined with a restriction order (s.41 MHA 1983), which means the offender can only be discharged with the consent of the Secretary of State for Justice, providing an extra layer of public protection. These disposals reflect a policy choice that for certain mentally disordered offenders, the primary need is for medical treatment within a secure setting, rather than punishment in a prison. However, access to these services is limited, and many offenders with mental health problems still end up in prison, where the support available is often inadequate.
Conclusion
In conclusion, criminal psychology offers a range of theories to explain the complex motivations and thought processes that can lead to criminal behaviour, moving the discussion beyond simple notions of good and evil. Criminal psychiatry provides the practical link between these concepts and the legal system, offering expert assessment that allows the courts to apply legal principles of criminal responsibility. The law in England and Wales has established mechanisms, such as the defences of insanity and diminished responsibility, to accommodate cases where mental illness is a significant factor. Furthermore, through sentencing options like hospital orders, the system acknowledges that psychiatric care, rather than imprisonment, is sometimes the most appropriate response.
Despite this, a significant challenge remains. The high prevalence of mental ill-health in the prison system suggests a systemic failure to divert vulnerable individuals towards care. While legal frameworks exist, their application is often constrained by a lack of resources and the enduring tension between the goals of punishment and rehabilitation. Ultimately, balancing the need to hold individuals responsible for their actions with the ethical and practical necessity of providing psychiatric care to those who need it remains one of the most difficult tasks facing the modern criminal justice system.
References
Bradley, K. (2009) The Bradley Report: Lord Bradley's review of people with mental health problems or learning disabilities in the criminal justice system. Department of Health.
Coroners and Justice Act 2009.
Eysenck, H. J. (1977) Crime and Personality. Routledge & Kegan Paul.
Homicide Act 1957.
M'Naghten's Case (1843) 8 ER 718.
Mental Health Act 1983.
Sutherland, E. H. and Cressey, D. R. (1974) Criminology. 9th edn. Lippincott.
Yochelson, S. and Samenow, S. E. (1976) The Criminal Personality: Volume I: A Profile for Change. Jason Aronson.

