In 2022, the National Police Agency changed the way it collects suicide data. Among the changes in the aggregation method, among the 7 categories, gender issues were changed to relationship issues, and 7 new items were added to the lower categories of the 23 categories, and the wording of some items was changed.

　In order to evaluate the impact of the change in the aggregation method for suicide statistics, the research group conducted a split time series analysis using data from January 2010 to December 1. We investigated changes in the level and trend of fatalities.

　As a result, the number of deaths for which the cause was known was 274,274, and the number of deaths after the new counting method was applied was 28,165. In 2021, the average number of cases for which the reason was identified was 1,723 cases per month, but after the change in the aggregation method in 2022, statistical analysis revealed that the number of cases for the past 12 years An increase of 839 cases was confirmed compared to the previous trend.

　This indicates that there has been a change in the level of aggregate values ​​compared to past trends. This trend was consistent across all categories (family problems, health problems, economic/lifestyle problems, work problems, relationship problems, school problems, and other reasons).

　Regarding cases of unknown reasons, there was an average of 2021 cases per month in 485, but in 2022 there was a decrease of 167 cases compared to the past trend.

　Although the results of this research make it impossible to make a simple comparison before and after 2022, the number of "reasons unknown" has decreased, and from a medium- to long-term perspective, this change will help clarify the reasons for modern suicide. It is hoped that there will be a connection.

Paper information:[JAMA Network Open] Early Outcomes of Changes to Collection of Suicide Data in Japan