Published online by Cambridge University Press: 01 August 2014
Phychoanalytic diagnostic methods and measures have been applied to 50 neurotic twins belonging to 21 MZ and to 16 same-sex and 13 opposite-sex DZ pairs. The 100 subjects consist of 64 adults and 36 children or adolescents. All 100 subjects were personally seen and psychologically examined. The mean intrapair difference of all MZ twin pairs amounts to 3.81 scaling points in a scored degree of severity of the neurosis; that of all DZ pairs to 5.00 points. The distribution of 657 neurotic symptoms in a chi-square table of the 21 MZ and 29 DZ twin pairs shows that 32.7% of the symptons are concordant in the MZ sample, but only 16.7% in the DZ sample. Hereditary influence could be shown in the manifestation of neurotic depressive symptoms, maladaptive oral and aggressive behavior, as well as in schizoid behavior deviations. Hereditary factors play a role in the formation of the neurotic character structure.
Regarding the environmental pathogenic factors, subjects more heavily stressed in early childhood were found, on the whole, more severely neurotic in later life.