Objective: This review, which was registered with PROSPERO (CRD42021237988), aimed
to systematically extract common elements in the hikikomori definition or criteria applied by
researchers and examine cultural differences and chronological changes in the
demographic characteristics of hikikomori individuals such as age, gender and hikikomori
duration. Method: For inclusion in the review, the hikikomori criteria, age and gender of the
hikikomori individuals had to be specified, and the article had to be peer-reviewed and …