Reviewing the criteria for determining competency at the trial

A crime can be committed only when the act must be both constitutive and unlawful, and the actor must be responsible. Regarding the nature of responsibility, common views and judicial precedents define responsibility as the possibility of accusation against an actor in accordance with normative responsibility. Competency have been an issue in society. In criminal proceedings, criminal suspects or accused persons often claim incompetency or limited competency due to a condition of unconsciousness or a feeble-minded condition. However, the majority of the public has strong doubts about the application of the competency provisions of the Criminal Act to reduce the sentence of such persons. The recognition of competency is often in conflict with the public's sense of law. Consequently, it is necessary to clarify the criteria for judgment. Although many meaningful studies on competency has been published, the criteria for determining competency are still unclear. Even though it is relatively clear that the methodology for determining competency is made from a normative perspective, based on a mix of biological and psychological factors, it is unclear how these factors are materialized at what stage in criminal proceedings. In practice, judicial precedents have revealed different attitudes. Therefore, this study focused on the judicial determination of competency. Specifically, this study analyzed the statistics of crimes committed by those with mental disorders and then reviewed the current state of the theoretical debate on determining competency. Afterward, this study analyzed cases of disagreement between the appraiser and the judge and clarified the judge's argumentative attitude. This study also suggested ways to improve the validity of the criteria for determining competency.