Until a few years ago it was believed that ADHD was a rare thing among girls and/or women and would occur perhaps only in the relation 1:9 (1 girl to 9 boys). This looks however completely different when talking to mothers in self-help groups or adults in other associations. Here it seems as if many more women than what is known are suffering from ADHD and more women than men are looking for psychotherapeutic assistance.
Most women with ADHD experience that the ADHD symptomatology changes as a function of the hormones. This is also a reason why some of the serious ADHD symptoms only are noticeable in puberty, then however visible more as puberty crisis or by developing secondary disorders (e.g. eating disorders, drug problems, depressions). Due to formal reasons it is not really possible to make an ADHD diagnoses at this point because the symptoms are supposed to have an onset before the age of 7.
Here the symptoms can differ clearly between boys and girls since boys get noticed by there impulsive and disturbing behavior due to the hyperactivity.
A typical experience of girls with ADHD is that they get along quite well in primary school because of the strict structure and clear instructions. When in secondary and high school many girls compensate the deficits in concentration by excessive efforts and an extreme repeating of the material. It is hard for them to follow instructions and they can look as if they are absent or daydreaming. They do, however, understand the content of the instructions without any problems and are able to do homework by themselves.