Activating effects of androgens on cognitive performance: Causal evidence in female-to-male transsexuals

Administered a battery of visuospatial and verbal ability tests to a group of 22 female-to-male transsexuals (aged 18-49 yrs), shortly before and 3 mo after the start of androgen treatment. Instruments included the Rotated Figures test, Word Production Categories test, Sentence Production, Letters test, and Verbal Reasoning test. The administration of androgens was clearly associated with an increase in spatial ability performance. In contrast, it had a deteriorating effect on verbal fluency tasks and no effect on verbal reasoning. Specifically, 77% of Ss improved in spatial ability, whereas 94% worsened in word production and 83% in sentence production.