The relationship between addiction and hikikomori tendencies: a case-control study.

Aim: The present study examined the relationship between addiction and hikikomori (extreme social withdrawal) symptoms.

Method: A group of clinically referred addiction patients ( = 31) and a group of age- and gender-matched non-clinical controls ( = 34) completed a self-report scale for measuring hikikomori symptoms (the Hikikomori Questionnaire-25) along with some other questionnaires assessing substance use (frequency and severity) and quality of life.

Results: The results showed that addiction patients displayed significantly higher levels of hikikomori symptoms than the non-clinical control (Cohen's = 3.