Sex differences in dopamine receptors and their relevance to ADHD

Gender differences in ADHD may be attributable to gender differences in dop amine receptor density. Striatal male D-2 receptor density increases 144 +/ - 26% between 25 and 40 days (the onset of puberty), while female D-2 recep tor density increases only 31 +/- 7%. Male receptor density is then sharply eliminated by 55% by adulthood. Periadolescent females show little overpro duction and pruning of striatal D-1 and D-2 receptors, though adult density is similar to males. The rise of male, but not female, striatal dopamine r eceptors parallels the early developmental appearance of motor symptoms of ADHD and may explain why prevalence rates are 2-4 fold higher in men than w omen. Pruning of striatal dopamine receptors coincides with the estimated 5 0-70% remission rate by adulthood. Transient lateralized D-2 dopamine recep tors (left > right) in male striatum may increase vulnerability to ADHD. Mo re persistent attentional problems may be associated with the overproductio n and delayed pruning of dopamine receptors in prefromal cortex. Difference s in D-1 receptor density in nucleus accumbens may have implications for in creased substance abuse in males. (C) 2000 Elsevier Science Ltd. All rights reserved.