• In a study of nine Klinefelter syndrome patients obtained from a military population, all were found to have normal electroencephalograms (EEGs), all were clinically euthyroid, and had normal thyroid function test results. All had normal verbal and nonverbal IQs and no evidence of neurologic dysfunction on psychological testing. There was a high incidence of personality maladjustment as indicated by both the Minnesota Multiphasic Personality Inventory and individual psychiatric evaluation. No particular personality pattern appeared typical for the group as a whole.

Neurologic dysfunction, as manifest by EEG abnormality, mental retardation, or neuropsychological test deficits, and hypothyroidism are not necessarily associated with Klinefelter syndrome. Likewise, although the incidence of personality disorders may be strongly associated with this disorder, no specific personality type appears especially characteristic of the syndrome.