ACTIVATING EFFECTS OF ANDROGENS ON COGNITIVE PERFORMANCE - CAUSAL EVIDENCE IN A GROUP OF FEMALE-TO-MALE TRANSSEXUALS

It is still unclear whether sex differences in cognitive functioning a re mainly due to perinatal organizing effects of sex hormones on the b rain, or to activating effects in adulthood. In a group of 22 female-t o-male transsexuals a battery of visuospatial and verbal ability tests was administered twice: shortly before and 3 months after the start o f androgen treatment. The administering of androgens was clearly assoc iated with an increase in spatial ability performance. In contrast, it had a deteriorating effect on verbal fluency tasks. This study offers preliminary evidence that androgens directly and quickly affect cogni tive performance in females.