The medico-legal assessment of mental fitness in criminal cases primarily aims to determine the individual's capacity to understand the nature of the crime and to distinguish right from wrong. This evaluation is crucial to establish criminal responsibility, as mental illness or impairment may exempt a defendant from legal culpability under the law. It helps the court decide whether the accused was mentally competent at the time of the offense and during trial proceedings. Assessing mental fitness ensures justice and appropriate legal outcomes based on the defendant’s mental state rather than solely on the criminal act itself.

Reference: Principles of Forensic Medicine, K.S. Narayan Reddy, 4th Edition.