Criminal insanity and mental health

The mental state of someone charged with a crime may be considered at 2 different stages:

• Before or at the start of the trial, and
• At the decision on guilt.

Before or at the start of the trial, if a person is suffering from a mental disorder, they may be considered unfit to be tried. If that happens, no trial goes ahead.

If a trial is held and the person is considered to have committed the offence but was insane at the time, a verdict of not guilty by reason of insanity may be reached.

In murder cases, the concept of diminished responsibility may be used to replace a verdict of murder with a verdict of manslaughter.

Legislation on criminal insanity

People who are charged with a criminal offence and who are suffering from a mental disorder are dealt with under the Criminal Law (Insanity) Act 2006 as amended by the Criminal Law (Insanity) Act 2010.

What is a mental disorder?

A mental disorder is defined in the 2006 Act as including mental illness, mental disability, dementia or any disease of the mind but does not include intoxication (drunkenness).

A judge decides whether or not a person is fit to be tried.

A person may be considered unfit to be tried if they:

• Cannot understand the charge, or
• Cannot give directions to a legal team, or
• Cannot challenge jurors, or
• Cannot follow the evidence

If a person is considered unfit to be tried, that is not a decision on their alleged criminal activity. If someone is found to be unfit to be tried, the trial is postponed.

If the trial is postponed, the judge then decides what happens next.

For example:

• The person may be committed to a psychiatric hospital or unit if they are considered to be suffering from a mental disorder and need in-patient treatment.
• The person may be committed to a psychiatric hospital or unit for 14 days to establish if they should be sent for treatment. The person may appeal against a committal order.
• The person may be sent for out-patient psychiatric care.

If the judge considers that a person is unfit to be tried and that there is a reasonable doubt the person committed the alleged crime, the person may be acquitted.

The Director of Public Prosecutions or the accused person can appeal against a decision that they are unfit to be tried.

Insane at the time of the offence

A person will be considered legally insane if they were suffering from a mental disorder at the time of the offence and, as a result,

• Did not understand what he or she was doing or
• Did not know what he or she was doing was wrong or
• Was unable to not commit the crime

If someone is considered to have committed the offence but was insane at the time, the verdict may be not guilty by reason of insanity. This decision is made by a jury where the case is tried by a jury. Where there is no jury, the decision is made by a judge.

If this verdict is reached, the judge may order that the person be committed to a psychiatric hospital or unit.

If a person is charged with murder, they may get a verdict of not guilty by reason of insanity.

The concept of diminished responsibility in murder cases is provided for in The Criminal Law (Insanity) Act 2006. This reduces a verdict of murder to a verdict of manslaughter.

The verdict is available where a person does not meet the test for a verdict of not guilty by reason of insanity but they were suffering from a mental disorder which substantially diminished their responsibility for the killing.

Sentence for diminished responsibility

If a person is convicted of murder, they must get an automatic life sentence.

If a person is convicted of other crimes, the judge has discretion on sentencing so they can consider any diminished responsibility that may exist.

However, if a person is charged with murder and successfully pleads diminished responsibility, then the verdict is manslaughter. The judge can sentence the person to any appropriate length of time in prison.

The Mental Health (Criminal Law) Review Board reviews the detention of those found not guilty by reason of insanity or unfit to be tried, who have been detained in the Central Mental Hospital.

At present, the Central Mental Hospital is the only designated centre.

The Review Board also is responsible for people who have been convicted of offences and who become mentally ill while serving their sentences.

The Review Board must consider:

• The welfare and safety of the person whose detention it reviews, and
• The public interest.

It may assign a legal representative to the person unless the person proposes to get one.

The Board has a legally qualified chairperson and must have at least one consultant psychiatrist It must review each detention at least once every 6 months.

Find out about legal representation in criminal cases.

The Mental Health Commission has information on your rights:

• Know your rights: a guide for involuntary patients receiving mental health treatments (pdf) and
• Your treatment options: a guide for those accessing in-patient mental health care (pdf).

Find more about sentencing at criminal trials.