Epidemiological aspects of intermittent explosive disorder in Japan; prevalence and psychosocial comorbidity: Findings from the World Mental Health Japan Survey 2002-2006

The purpose of the present study is to evaluate the prevalence of intermittent explosive disorder (IED) as well as its comorbidity with other mental disorders in a Japanese community sample. Subjects were 4,134 residents in selected sites in Japan. Diagnoses of mental disorders are based on the World Mental Health Survey Initiative Version of the World Health Organization Composite International Diagnostic Interview. Lifetime and 12-month prevalence of IED were 2.1% and 0.7%, respectively, whereas those of narrow IED were 1.2% and 0.6%, respectively. Male gender and young age were positively associated with an increased prevalence of IED. Mood and anxiety disorders as well as suicidal ideation were shown to be associated with IED in both genders. The overall association between anxiety disorders and IED was stronger in women than in men. Positive association of substance use problems with IED was also observed. Similar findings were observed between those psychosocial factors and narrow IED. These results suggest that people having those mixed complications might have a high suicidal risk. Further research using psychological measures for anger suppression will lead to more thorough understanding of the effects of IED on psychosocial comorbidity and suicidal risk.