Personality and suicide risk: the impact of economic crisis in Japan

Background. The interactive effect of personal factors and social factors upon suicide risk is unclear. We conducted prospective cohort study to investigate whether the impact of the economic crisis in 1997-1998 upon suicide risk differed according to Neuroticism and Psychoticism personality traits. Methods. The Miyagi Cohort Study in Japan with a follow-up for 19 years from 1990 to 2008 has 29432 subjects aged 40-64 years at baseline who completed a questionnaire about various health habits and the Japanese version of the Eysenck Personality Questionnaire - Revised Short Form in 1990. Results. The suicide mortality rate increased from 4.6 per 100000 person-years before 1998 to 27.8 after 1998. Although both Neuroticism and Psychoticism were significantly associated with an increased risk of mortality during the whole period from 1990 to 2008, the impact of the economic crisis upon suicide risk differed between the Neuroticism and Psychoticism personality traits. Compared with the lowest category, the hazard ratios (HRs) for the highest Neuroticism increased from 0.66 before 1998 to 2.45 after 1998. On the other hand, the HRs for the highest Psychoticism decreased from 7.85 before 1998 to 2.05 after 1998. Conclusions. The impact of the 1997-1998 economic crisis upon suicide risk differed according to personality. Suicide risk increased among these with higher Neuroticism after the economic crisis, but this was not the case for other personality subscales.