Comorbid social withdrawal (hikikomori) in outpatients with social anxiety disorder: Clinical characteristics and treatment response in a case series

Background: Severe social withdrawal (called hikikomori, and defined as isolation lasting more than six months and not due to an apparent mental disorder) has drawn increasing public attention in Japan. It is unclear whether hikikomori is merely a symptom or syndrome of social withdrawal. Aim: To evaluate this phenomenon in relationship to social anxiety disorder (SAD), as few previous studies have. Methods: One hundred and forty-one consecutive patients with SAD diagnosed according to DSM-IV criteria by a semi-structured interview were treated with a combination of psychotherapy, pharmacotherapy and group activity. Results: Twenty-seven (19%) SAD patients fulfilled the criteria for hikikomori, and these patients had earlier onset, more symptoms and less education than non-hikikomori SAD patients. Only 33% of hikikomori SAD patients spontaneously complained of SAD symptoms at first visit. There were no diagnostic differences between hikikomori and non-hikikomori SAD patients, except that comorbid obsessive-compulsive disorder was more frequent in hikikomori SAD patients. Functional impairment in 10 (37%) hikikomori SAD patients improved after several years of combination therapy. Conclusion: Hikikomori may serve as a proxy for a severe form of SAD. Patients with comorbid SAD and hikikomori have lower treatment response rates than those with SAD alone.