Background: Social isolation is associated with significant morbidity and mortality. A severe form of social isolation or social withdrawal, called hikikomori in Japan, has been described, but controversy over the etiology and universality of the phenomenon remains.
Method: Case report.
Results: Diagnostic assessment by structured clinical interview and psychometric tools revealed hikikomori and underlying bipolar disorder, in which the patient's social withdrawal occurred exclusively during major depressive episodes. The patient declined pharmacotherapy, but his hikikomori and depression went into remission after 25 sessions of cognitive behavioural therapy targeting his social isolation.
Conclusions: This is the first reported case of hikikomori in the Americas. It illustrates the association between hikikomori and a mood disorder, and suggests the importance of international study of the prevalence and potential treatment strategies for severe social isolation.
Keywords: Social isolation; bipolar disorder; hikikomori; social withdrawal.