The insanity defence is a legal principle that can be applied when a person accused of a crime has serious mental disorder that may have affected their ability to recognise or have control over their wrongful actions. However, there is still a bridge between being diagnosed with mental illness and being classified as “legally insane.” The exact rulings behind this vary between legal systems, but the central issue is deducing whether a person’s mental state has any effect on their criminal responsibility at the time of the offence. This raises the important question: does mental disease reduce responsibility for an action, and if so, to what extent?
What does it mean to have a mental disease?
By definition from the World Health Organisation, mental disease is characterised as a clinically significant disturbance in an individual’s cognition, emotional regulation, or behaviour. Some examples of mental illnesses are schizophrenia, severe bipolar disorder, depression, generalised anxiety, and many other conditions that, in some circumstances, can have a serious effect on an individual’s understanding of reality. However, a diagnosis alone is not enough to determine if an insanity defence is necessary.
This creates an important distinction between being classed as mentally ill and being “legally insane.” A person can have a diagnosed mental illness while still having a clear understanding of what they are doing even if it is wrong. This is why legal insanity is a far narrower concept that zeros in on the effect of the person’s condition on their mental capacity at the time of the crime, rather than asking if they have a psychiatric diagnosis.
How much control does someone have over their actions?
Criminal responsibility can be viewed as a spectrum. On one end, a person understands their actions and their consequences, therefore they have significant control over their actions. On the other end, a severe mental disorder may prevent a person from understanding reality, or perhaps they may even lack the capability in recognising the nature or wrongfulness of their actions. Where someone falls on this spectrum is dependent on several factors: severity of their condition, their symptoms at the time of the offence, their ability to grasp what they were doing, and whether they view their actions as just. However, this can be a challenge as even if two individuals are diagnosed with the same mental disorder, symptoms may vary in them as mental disorders do not affect everyone in the same way.
How does a court prove insanity?
Courts use legal tests to prove whether or not a defendant meets the requirements for an insanity defence. While these tests may differ between different countries and legal systems, the general idea remains the same. For example, the individual’s mental state at the time of offence, alongside any psychiatric or psychological assessments alongside medical records, statements from witnesses, and any other evidence. Some common assessments conducted to gain evidence are:
- The M’Naghten Rule: also known as the right and wrong test, is a legal standard that originated from England in 1843. This is used to determine whether the defendant has no understanding of the nature or quality of what they were doing, or if they understood what they were doing but does not view it as wrong.
- The irresistible impulse test: This assesses the level of control the defendant possesses when it comes to making a decision. The examiner can then determine whether the defendant tends to act out more brashly or calmly in specific situations.
- The Durham/Product test: This testing takes a different approach to determine whether the individuals criminal conduct was the direct result of their mental disease without external factors taken into consideration.
The court must then determine the reliability of all their examinations alongside with the help of medical professionals who assess the defendant’s symptoms and any medical history. However, the final verdict about criminal responsibility lies with the court with the accuracy of the judgement is dependant on the accuracy of the evidence supplied.
What problems can psychiatric testing create?
Although many tests are conducted to increase reliability of evidence, there are always drawbacks to the methods used by the court. For instance, psychiatric assessments are not always straightforward. Mental disorders can express different symptoms in different people, and symptoms can also change over time. Additionally, some individuals may exaggerate symptoms, deliberately hide them, or possess genuine struggle to describe their experiences. Another struggle is that these assessments often take place after the crime, hence, this makes the process partly dependant on the past rather than a direct observation. These limitations do not make psychiatric evidence useless, but they show why determining legal insanity can be proven a struggle.
Overall, the insanity defence attempts to balance two important principles: holding people accountable for their crimes while having recognition that severe mental disease can sometimes play a role in their actions. While mental illness alone should not excuse an individual from criminal responsibility, they should not be ignored completely either when it significantly affects the individual’s ability to understand and control their actions. Ultimately, the extent to which mental disease can justify a crime is heavily dependent on the defendant’s mental state, the evidence available, and the legal tests applied by the court.