Sex differences in dopamine receptors and their relevance to ADHD

Gender differences in ADHD may be attributable to gender differences in dopamine receptor density. Striatal male D-2 receptor density increases 144 +/- 26% between 25 and 40 days (the onset of puberty), while female D-2 receptor density increases only 31 +/- 7%. Male receptor density is then sharply eliminated by 55% by adulthood. Periadolescent females show little overproduction 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 receptors parallels the early developmental appearance of motor symptoms of ADHD and may explain why prevalence rates are 2-4 fold higher in men than women. Pruning of striatal dopamine receptors coincides with the estimated 50-70% remission rate by adulthood. Transient lateralized D-2 dopamine receptors (left > right) in male striatum may increase vulnerability to ADHD. More persistent attentional problems may be associated with the overproduction and delayed pruning of dopamine receptors in prefromal cortex. Differences in D-1 receptor density in nucleus accumbens may have implications for increased substance abuse in males. (C) 2000 Elsevier Science Ltd. All rights reserved.