Irresistible impulse as a defence in criminal law differs from the M'Naghten rule in that it addresses:

• A Cognitive incapacity — the accused did not know the nature of the act
• B Perceptual incapacity — the accused had hallucinations at the time
• C Volitional incapacity — the accused could not control behaviour even if knowing it was wrong ✓
• D Amnestic incapacity — the accused could not recall committing the act

Explanation

The M'Naghten rule (reflected in IPC Section 84) focuses exclusively on cognitive defect: the accused did not know the nature of the act or that it was wrong. Irresistible impulse doctrine, recognised in some jurisdictions, extends the defence to volitional defect: the accused knew the act was wrong but, because of mental disease, could not control their conduct (will power was completely destroyed). Indian courts have not uniformly adopted irresistible impulse as a standalone defence, but it is frequently discussed in forensic psychiatric reports and examined in NEET PG.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.