Effects of "Shinkeishitsu" on Occupational Stress in Japanese Workers

MDD has exceeded that of diabetes (about 2.37 million people) and cancer (about 1.52 million people) [1].Mental illness is now so prevalent in Japan that it is considered one of the Five Major Diseases in Japanese medicine, and its effects are serious.The survey of completed suicide revealed that mental illness is a particularly important cause of suicide.By 2011, the number of suicides per year in Japan had exceeded 30,000 people [2].Moreover, there is an increase in the number of various types of workers experiencing mental illness Ministry of Health [1], particularly mood disorders.Therefore, more aggressive efforts should be made to monitor mental health in the Japanese workplace.Recently, the number of patients with not only MDD, but also MDD with atypical features or adjustment disorders, which are presumed to develop from one's personality, continues to rise among Japanese workers [3,4].A number of studies have investigated the association between personality traits and job stress.The traditional Japanese personality "shinkeishitsu," which also relates to the Japanese-culture-bound syndrome "taijin-kyofu-sho," has become almost outdated, even in modern Japanese psychiatry [5].Morita [6] developed a psychiatric classification system and coined the term "shinkeishitsu," or a "nervous trait," to identify a group of related neurotic sufferings and symptoms mediated by certain common psychological, psychosomatic, and somatopsychic processes [7].Morita shinkeishitsu has three dimensions: symptoms, symptom formation, and character structure.These dimensions include the following: 1) clinical characteristics of the symptoms: ego dystonia of anxiety, adaptation anxiety, defensive oversimplification, self-specialization, symptom-overcoming attitude and problem acknowledgement; 2) symptom formation: psychic interaction and conflicts between the ideal and reality; and 3) character structure: having two symmetric aspects of both "Introversion and Fragility" and "Obsessive and Self-empowering Characteristics" [8].In addition, an introversiveand fragile aspect must have at least one of these five characteristics: introversion, worrisomeness, interpersonal fragility and hypersensitivity, hypochondriasis, or passivity.In a similar way, anobsessive and self-empowering aspect must have at least one of these five characteristics: desire for perfection, desire for superiority, desire