[Today’s Insanity Defense ①] As Mitigation Becomes Harder... Defendants’ Views on the ‘Insanity Defense Mitigation System’

Appealing for Leniency Aiming at Suspended Sentence... Claims of Insanity and Blackout
Public Outrage Over Jo Doo-soon's 12-Year Prison Sentence... 2018 Law Amendment Allows "Possible Reduction"

Choi (29, male) was brought to trial on charges of sexual assault after following his friend's girlfriend to the restroom and forcibly touching her at a bar in Gangnam-gu, Seoul, in August 2020. Choi's side argued, "The victim's boyfriend is a longtime friend. We believe neither the victim nor the boyfriend is lying," but also claimed that Choi was intoxicated and in a state of 'diminished mental capacity' at the time of the incident. After reviewing evidence such as CCTV footage, the court did not accept the diminished mental capacity claim, and Choi ultimately did not receive any sentence reduction.

The 'diminished mental capacity' sentence reduction has long been at odds with public sentiment. Diminished mental capacity refers to a psychological condition where the ability to distinguish objects and make decisions is impaired, leading to a reduced level of punishment. Article 10, Paragraph 1 of the current Criminal Act stipulates that acts committed by a person in a state of mental incapacity are not punishable, while Paragraph 2 of the same article states that acts by a person with diminished mental capacity may be subject to sentence reduction. A representative case that sparked public outrage was the 2009 trial of Jo Doo-soon for rape and injury. At that time, the court considered that he was intoxicated and in a state of diminished mental capacity and sentenced him to 12 years in prison, which faced strong public criticism.

Subsequently, in December 2018, Article 10, Paragraph 2 of the Criminal Act was amended from "shall reduce" to "may reduce" sentences for acts committed by persons with diminished mental capacity. This change made the sentence reduction for diminished mental capacity discretionary rather than mandatory for the court. According to legal circles, the number of defendants claiming diminished mental capacity has generally decreased recently. Attorney Kim Miri of Dongin Law Firm stated, "Cases claiming diminished mental capacity itself are rare nowadays," and added, "Even when such claims are made, due to the amendment of the Criminal Act, actual sentence reductions are uncommon." In Choi's case, his lawyer said in court, "We claim diminished mental capacity, but we understand that courts recently rarely recognize it as grounds for sentence reduction."

Although the Trend Is to Reject Diminished Mental Capacity... Defendants Still Aim for Sentence Reduction and Probation

Nevertheless, defendants continue to claim diminished mental capacity in criminal courts. This is to utilize the principle of responsibility, which states that "no punishment can be imposed on one who is not responsible." Courts still do not view the responsibility of a mentally healthy person and a person with mental illness who commit crimes as equal. Even if a crime is committed with impaired intellectual or volitional capacity, the defendant is considered to have reduced responsibility, which may lead to a lighter sentence.

Sentence reduction can also lead to probation. Probation is possible only when a prison sentence of three years or less is imposed. While discretionary sentence reduction can extend up to three years and six months, diminished mental capacity is a representative factor that can reduce sentences beyond that. Judge A of the Seoul Central District Court stated, "Recently, many penal laws have set minimum sentences, which creates room for considering sentence reductions."

Some defendants claim mental incapacity instead of diminished mental capacity, which is not an absolute mitigating factor. A man in his 60s who suffered from delusions and auditory hallucinations and killed a village chief sought recognition of mental incapacity up to the Supreme Court but was ultimately sentenced to 13 years in prison. The court pointed out, "Considering the circumstances at the time, the defendant's psychological state, and the characteristics of the mental illness experienced, it can be seen that the defendant was in a state of diminished mental capacity due to symptoms caused by delusions and hallucinations, but it does not appear that the defendant reached a state of mental incapacity beyond that."