Attention deficit hyperactivity disorder (ADHD) is defined by the presence of symptoms of inattention, hyperactivity and impulsivity. To receive a diagnosis of ADHD, six or more symptoms of inattention, hyperactivity and impulsivity must be present for at least 6 months and for children up to the age of 16. Symptoms include difficulties in sustaining attention, difficulties retaining information, difficulties in social etiquette and difficulties with impulse control.

Boys are more likely to present inattentive and hyperactive behaviours compared to girls therefore are more likely to receive a diagnosis of ADHD. Researchers have proposed the ratio of boys to girls with ADHD estimated at between 2:1 and 9:1.

In addition to 'real' differences in underlying symptoms of ADHD, skewed gender ratios could highlight a recognition issue whereby girls are less well-identified and boys are over-identified with ADHD. So the high boys/girl ratios in ADHD diagnosed children are due to a) real differences in symptomology and b) an additional referral or recognition bias. This could be due to girls potentially hiding a childhood history of hyperactivity/disruptive behaviours hence may have not been clinically spotted. Alternatively, it could be because boys typically present more disruptive behaviour therefore more easily spotted than girls, who are more likely to internalize distress.

Other than co-occuring symptoms on which boys and girls with diagnosis differ, differences in cognitive abilities could be potential triggers of referral bias. Higher scores on working memory and processing speed are more pronounced in boys with ADHD compared to girls. If girls with ADHD diagnosis have lower abilities than boys, it may be because they need more severe symptoms before they are referred.

This project highlights a public health concern as gender-sensitive diagnosis could lead to boys being over-diagnosed with ADHD therefore potentially damaging their life opportunities. Also the under-diagnosis of girls may mean they miss out on treatments that would benefit them. This project aims to investigate this gender bias in the identification of diagnosing ADHD.