I'd be careful assuming this is Japanese. Cultural Variation in Past Hikikomori Experiences of University Students (2019) - DOI: 10.1080/00221325.2019.1633618

I'd be careful assuming this is Japanese. Cultural Variation in Past Hikikomori Experiences of University Students (2019) - DOI: 10.1080/00221325.2019.1633618 Percentages of participants reporting past experiences of Hikikomori - Nigeria 20.90 % Singapore 9.50 % United States 2.70 % You can disagree on a self reporting study, but Hikikomori will exist in the US, if you want to say it's insignificant to Japan you do need indicate what the rates are.