Girls are much less likely to be diagnosed with ADHD than boys and this presents a puzzle as to why this is. There could be a genetic reason why girls are less likely to get ADHD. For example, females have two X-chromosomes whilst males only have one. This means that if ADHD is triggered by genetic code then a girl, having a second copy of the chromosome, can 'replace' the ADHD code with neurotypical code. Boys do not have this option. Another reason why boys are more frequently diagnosed is because of gender differences in behaviour.
Gender plays a significant role in shaping the behaviour of everyone. Gender influences the way people interact and socialise with others, their motivation and attitudes to learning and working and the expression of their emotions. Gender is complex and I want to avoid stereotyping boys and girls. However, it is probably fair to say that boys are more likely to express negative emotions much more explicitly and immediately than girls in most contexts other than the home. Girls are more likely to 'bottle things up' inside and hide how they are feeling until eventually they 'explode' at home often over something quite trivial. These gender generalisations about all children are important when considering how the traits of ADHD impact the individual and how their needs present to the observer.
A diagnosis of ADHD requires evidence of the impact of symptoms in two settings. This is usually in school and the home with both teachers and parents completing ADHD questionnaires for the consultant. Though girls with ADHD will experience the same level of difficulties with learning as boys they are often better at masking these difficulties. For example, asking a friend what they need to do or sometimes copying a friend's work. They are more likely to remain quiet if their understanding is questioned by an adult. Teachers can sometimes be slightly more dismissive of girl's attention and concentration difficulties and use labels such as 'forgetful', 'ditsy' or 'daydreamer' to explain away their behaviour.
ADHD girls with impulsive talkative traits may be described as 'chatty' whilst boys may be more likely to have the same behaviour described as 'distracting others' or even 'disruptive'. The gender differences in the way boys and girls react to being told off by the teacher may partly explain this. Boys may sometimes react negatively to being challenged by a teacher and this escalates the situation. Girls are generally more likely to react submissively and/or apologetically and thereby de-escalate the situation. The 'reputation' a child has may also influence how a teacher perceives, interprets and records 'low level distracting' behaviours. Thus, more extreme aggressive and impulsive behaviours that have been exhibited by an ADHD child may mean that staff are more alert to them at all times and therefore more likely to pick up on any low level behaviour. In contrast an ADHD child who tends to direct their frustration and anxiety internally may be less noticed. As girls more often internalise feelings than boys this may also explain differences in ADHD diagnosis rates.
The needs of an ADHD girl may become more apparent after transition to secondary school. Many ADHD students struggle with organisation, time keeping and planning and these are skills that surviving secondary education require. Established friendship groups become disrupted by transition and it can become more difficult to mask the learning difficulties associated with ADHD. At the same time the curriculum becomes increasingly specialised and technical and places demands on working memory and motivational processes that many ADHD students find challenging. As a result it can be difficult to become motivated to do challenging work on topics that they have little or not interest in. Without the close and supportive relationship that is easier to establish with primary class teachers than secondary subject teachers, some ADHD girls will start to reject learning and the value of education. There is also a difference between the genders in how they cope with educational failure. Boys tend to lay the blame for their failure elsewhere whilst girls more readily blame themselves. This means that girls are much more likely to suffer from poor self-esteem.