
Mental illness raises significant legal and ethical questions about criminal responsibility. Courts must determine whether an accused individual had the mental capacity to understand their actions at the time of the offense. This article explores the laws governing criminal responsibility, historical perspectives, civil and criminal liability, methods of proving insanity, and the types of punishments applicable.
Legal Framework on Criminal Responsibility of the Insane
International and National Laws
Most legal systems recognize that individuals who cannot distinguish right from wrong due to mental illness should not be held fully responsible for their actions. Key legal principles include:
- M’Naghten Rule (1843, UK) – An individual is not criminally responsible if, due to a mental disorder, they could not understand the nature of their act or distinguish right from wrong.
- Durham Rule (1954, USA) – A person is not responsible if their unlawful act resulted from mental illness.
- Insanity Defense Reform Act (1984, USA) – Limits the insanity defense to cases where a severe mental disorder prevented the defendant from understanding their actions.
- Indian Penal Code (IPC), Section 84 – States that nothing is an offense if done by a person incapable of knowing the nature of the act due to unsoundness of mind.
- Bangladesh Penal Code, Section 84 – Follows similar principles as IPC regarding mental incapacity as a defense.
Historical Development of Insanity Laws

Ancient societies often treated mentally ill offenders with religious or supernatural interpretations. During the Middle Ages, such individuals were confined rather than punished. The M’Naghten Rule marked a shift towards a legal standard, influencing most modern insanity laws. Over time, courts refined these rules, incorporating psychological assessments to determine mental responsibility.
Civil vs. Criminal Responsibility

Criminal Cases
- An insane person cannot form criminal intent, making them not guilty by reason of insanity (NGRI).
- Courts may order psychiatric treatment instead of imprisonment.
- The burden of proof lies on the defense to establish insanity.
Civil Cases
- Mental illness does not necessarily absolve a person of civil liabilities.
- In contractual disputes, courts assess whether the person had the mental capacity to enter into a legal agreement.
- Guardianship laws may apply to protect the interests of mentally ill individuals.
Proving Insanity in Court
To establish insanity, defense attorneys rely on multiple forms of evidence, including:
- Medical Records – Documented history of psychiatric illness.
- Expert Testimony – Psychiatric evaluations by forensic psychologists.
- Behavioral Evidence – Witness accounts of unusual or delusional behavior.
- Cognitive Assessments – Neuropsychological tests to assess decision-making abilities.
- Crime Scene Evidence – Actions suggesting lack of awareness or intent.
Types of Punishments for Insane Offenders

- Acquittal with Psychiatric Treatment – Courts often mandate treatment in a mental health facility.
- Diminished Responsibility – Some legal systems impose reduced sentences.
- Indeterminate Detention – Offenders may remain in psychiatric institutions until deemed fit for release.
- Supervised Release – In cases of partial insanity, courts may impose restrictions rather than incarceration.
FAQ about Criminal Responsibility of an Insane Person
1. What happens if an insane person commits a crime?
The court evaluates their mental state at the time of the crime. If proven insane, they may receive psychiatric treatment instead of imprisonment.
2. How can a lawyer prove insanity in court?
Lawyers present medical records, expert testimony, and behavioral evidence to demonstrate the defendant’s mental incapacity.
3. Is an insane person responsible for civil damages?
In most cases, mentally ill individuals may still be liable for civil damages unless they lacked the capacity to understand their actions.
4. Can an insanity defense lead to immediate release?
No. Courts may order confinement in a psychiatric facility instead of prison.
For further legal references, visit the United Nations Office on Drugs and Crime for international legal standards on criminal responsibility.
Sources:
- United Nations Office on Drugs and Crime (UNODC)
- American Psychiatric Association (APA)
- Indian Penal Code (IPC), Section 84
- Insanity Defense Reform Act (USA)