The Defence of Diminished Responsibility

Introduction

In recent times, there has been an increase in discussions around mental health and mental illness. Significant public interest and concerns have raised questions in relation to how these topics interact with the law, concepts of criminal justice and criminal responsibility. In most criminal matters, the mens rea, or mental state of a person is a key element of the offence. Murder is no exception to this general rule.

What is the Defence of Diminished Responsibility?

Diminished responsibility is a partial defence to a charge of murder as set out in Section 4A of the Offences Against the Person Act. In other words, diminished responsibility means that at the time of the offence, the person was suffering for a mental condition that impaired their judgement. This defence cannot be raised for other crimes such as robbery, rape and sexual offences since it only applies to a charge of murder, reducing it to manslaughter.

What must be proved?

For the defence of diminished responsibility to be successful, three (3) conditions must be proven. First, the accused persons must be suffering from an abnormality of the mind at the time of the killing. Secondly, that abnormality arose due to some disease/injury, or a retarded development of the mind or any inherent cause. Lastly, there must be a link between the abnormality of the mind and the cause of death. In law, the abnormality must have impaired his/her actions or omissions which caused the death.

What amounts to an abnormality of mind?

Diminished responsibility is concerned with a condition of the mind which substantially impairs mental responsibility. That condition of mind must be abnormal, meaning that it is different from that of an ordinary human being. This state of mind differs from what is considered normal and provides an explanation as to why the accused acted in the way that he did when he caused the death, and cannot be held fully responsible for his actions.

In looking at the state of the mind, the person’s perception, understanding, judgement and will are areas considered. Some examples of a person’s state of mind which differ  from what is considered normal include an accused person suffering from bipolar disorder, paranoid delusions, and schizophrenia.

What is a substantial impairment of mental responsibility?

The accused’s abnormality of mind must be substantial or, in other words, considerable. This means that the accused’s mind must have been significantly affected at the time of the offence. Therefore, even if an accused person knows what he is doing is wrong, he would have a substantial impairment of his mental responsibility if his abnormal mind prevented him from controlling his impulses or actions.

How do you prove the Defence of Diminished Responsibility?

The burden is on the accused to establish the defence of diminished responsibility. The tribunal must be satisfied that at the time of the offence, it was more likely than not that the accused suffered from an abnormality of mind in accordance with the defence of diminished responsibility.

Medical evidence is important when an accused person relies on the defence of diminished responsibility. For instance, medical reports, psychiatric evaluations and the evidence from Doctors, Psychiatrists and other experts can be used.

If the Defence of Diminished Responsibility is proved at trial, does the Accused person “walk free”?

Diminished responsibility is a partial defence. Where diminished responsibility is established, it reduces the accused’s culpability for his actions when he did the killing however, the accused will be guilty of manslaughter which carries a sentence from a fixed term of years and can be up to life imprisonment. Alternatively, the Court may detain the accused person in safe custody for as long as the Court thinks fit or necessary or order that the accused person be detained and treated as a mentally ill person.

Can a plea of guilty to manslaughter based on diminished responsibility be accepted by the State?

The Office of the Director of Public Prosecutions can engage in plea discussions with an accused person and accept a plea of guilty to manslaughter by reason of diminished responsibility even before a trial. In such a case, medical or psychiatric reports can be relied upon. Engaging in plea discussions in this way can also avoid a lengthy trial, distressing witnesses who would have to come to court to testify and save the resources of the State.

A challenge with plea discussions that can arise is the fact that the accused person must consent to the plea agreement and depending on the extent of his/her abnormality, they may not be able to consent due to lack of mental capacity.

Conclusion

The concept of diminished responsibility was designed to lessen the mandatory death penalty in those cases where persons were mentally impaired at the time of committing the offence of murder. Whilst there may be an urge to believe that persons frequently “play mad” or “act crazy” during the criminal process, the defence of diminished responsibility makes no provision for persons to be excused from criminal responsibility for their actions due to emotions such as jealousy and anger to which any normal person may be subject to from time to time. Rather, this defence focuses on persons with an abnormal mind and relies on expert evidence from trained professionals for its success.