Depression (DSM-Ⅲ, Axis-I: Major Depression, Single Episode with Melancholia, 296. 23) in a Monozygotic Twin Naoki Hayashi 1,2 , Shin Ihda 1,2 1Department of Neuropsychiatry, Branch Hospital, Faculty of Medicine, University of Tokyo 2Department of Neuropsychiatry, Niigata University School of Medicine Keyword: Monozygotic twins , Depression , Melancholia type , Discordance , Premorbid character pp.971-978
Published Date 1983/9/15
DOI https://doi.org/10.11477/mf.1405203644
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 We presented the case of a discordant male monozygotic twin of depression (DSM-Ⅲ, Axis Ⅰ : 296. 23), and compared developmental history, personality traits, and life history of this index twin (IT) with those of cotwin (CT).

 Because the discordant monozygotic twins have the same genetic predisposition, their discordance is not to be attributed to genetic factors, but rather to developmental and environmental difference. Therefore, we are able to investigate some aspects of the processes involved in the development of depression, including the development of the premorbid character, "Melancholia type"(Tellenbach),and depression-precipitating life events.

 We found several developmental and life historical differences between the twins. At birth, IT weighed 300g less than CT, and their physical unequality could be recognized until they were about 10 years old. During childhood, they were brought up strictly by their parents, and their mother forced them to study hard and to compete with each other academically. They worked hard, but IT was usually inferior to CT. IT tended to express his emotions snore openly, to be more active and to make friends more easily than CT. From adolescence IT tended to have "illusory feelings of unity with others" (Doi), and to make obsessive efforts in academics and sports, which was thought to be the first appearance of one of the characteristics of Melancholia type character. However, he sometimes failed to carry through his efforts, as he became bored. CT, on the other hand, was cool and constantly diligent, and excelled academically. In adulthood IT worked eagerly at his job, unconsciously craving for the acceptance of others. Devoted to his job, he internalized strict occupational morals to his superego, suppressed his emotional expressions, and his personality traits became very similar to those of the Melancholiatype. When he was 50 years old, under such stresses as the burden of his job and the death of his father, he was overcome by depression.

 We found IT's personality traits were like those of the Melancholia type, while CT's were cyclothymic (Kretschmer), but with some characteristics of the Melancholia type. We thought the twins to be genetically predisposed to be cyclothymic, but IT developed the Melancholia type character as pathological personality traits deriving from cyclothymia before the onset of depression.

 We further considered how environmental and developmental conditions, for example, IT's rejection by his mother in his nurturing environment, had influenced the genesis of the Melancholia type character and depression. We conjectured the developmental course of depression : Genetic predisposition of depression (cyclothymia)-Some defect in the nurturing environment-Deviant character development-Burden of his job-Development of the Melancholia type character-Depression-precipitating conditions-Onset of depression.

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