EEG differences in neurotic as compared with normal twin pairs.

The resting EEGs of 17 twin pairs originally traced through one neurotic co-twin (10 monozygotic and 7 dizygotic pairs aged between 18 and 63 years) have been described and compared with the neuroticism scores (Schepank, 1974) of these twins. EEG comparison according to the customary visual criteria failed to show any consistent EEG differences between monozygotic co-twins, whereas dizygotic pairs often showed EEG discordance. Computerized time-domain (interval-amplitude) analysis failed to show a higher degree of EEG discordance between neurotic MZ co-twins than between co-twins in 25 adult nonneurotic male MZ pairs (age range 18--33; mean age 22.9 years). There were no significant correlations between EEG differences and differences in the neuroticism score among ten MZ pairs traced through a neurotic co-twin. It is concluded that the individual and genetically determined EEG pattern is manifest even in the face of the long-lasting psychological alterations observed in neurotics.