Rates of ADHD Among Girls

Just boys have ADHD, right? Wrong. ADHD can affect girls, with recent estimates of ratios ranging from 2:1 to 6:1. Staller and Faraone [1] estimated that 32 million females worldwide have ADHD based on current information on prevalence and sex ratios, making the diagnosis of ADHD in females a major public health concern. This gender difference in prevalence, along with the likelihood of a referral bias that continues to under identify ADHD in females, has resulted in a much slower growing body of literature on the female ADHD profile. For a long time we largely didn’t know if the significant and global deficits that have been documented in boys with ADHD, such as having a hard time processing information, holding information on line, estimating time, and stopping a behavior once started [2-6], could be extrapolated to girls.

ADHD Symptoms in Girls

Along with the belief that ADHD doesn’t happen in girls came some studies suggesting that even if girls had ADHD, they weren’t as impaired as boys with ADHD [7]. These findings have since been disconfirmed and evidence is building that we can no longer ignore. Studies over the last decade consistently show that females struggle in similar ways to boys – forgetting things they need for school, having problems with speech and language, solving complex problems, having a hard time putting on the brakes, losing track of time, making more errors in their work and struggling academically [8-10]. This overall lack of gender differences in cognitive functioning has also been documented in an adult sample [11].

Some even find that girls with ADHD are more compromised in their intellectual functioning and may have poorer knowledge of vocabulary [12,13]. Lower scores on Block Design, a measure of perceptual and visual spatial reasoning, have been noted in ADHD girls compared to ADHD boys with performance on all other measure of cognitive functioning falling similarly across gender [14]. However other studies show that in some areas, boys may have more problems. For example, research on a New Zealand population found that although adolescent girls and boys with ADHD were struggling similarly cognitively [15], there was one noted difference: ADHD males showed evidence of greater inhibition than ADHD females – in other words, boys with ADHD may struggle more with stopping themselves once they have started. Newcorn and his colleagues [16] found the same thing: their sample of girls with ADHD made fewer impulsivity errors (commission errors) than the ADHD boys. 

Summary

In sum, although there are fewer females being diagnosed with ADHD, most studies have found few or no cognitive differences across the sexes in ADHD populations [17,18] with significant cognitive impairments across most areas of functioning (planning, set-shifting, working memory, attention, processing speed, executive function, naming speed, etc) evident in both males and females with ADHD compared with individuals without ADHD [11,15] [8,19,20]. However, stimulant medications (like Ritalin) have been known to influence outcomes of some studies (e.g., [7]), emphasizing the importance of considering the effect that medications can have on the results that have been reported. This finding also confirms that medications may be able to help with some of these complex academic activities. Overall though, the bulk of research to date is telling us one thing: don’t ignore the ADHD girls, they need help. More similarities than differences have been noted between the sexes in ADHD populations and therefore, we can expect similar problems in ADHD individuals, regardless of the sex of the individual concerned.

While deficits are found in all studies investigating neurocognitive functioning of ADHD populations, the fact that inconsistencies are noted across the studies in which tests show deficits implies that variability in neurocognitive performance in the ADHD population may be the norm rather than the exception, making the task of finding which brain regions are involved in ADHD symptomatology all the more difficult.

There is some evidence to suggest that males and females with ADHD may have different neural substrates for their behaviors, explaining why developmental differences exist (like girls exhibiting more attentional problems and less hyperactivity compared with boys). Hermens et al. [21] determined that women with ADHD (and not men) had substantially reduced skin conductance (a measure of autonomic arousal) whereas men with ADHD (and not women) had increased EEG theta activity (an inverse measure of arousal). Further research may show that distinct mechanisms may underpin the behaviour across the sexes, accentuating the importance of not assuming that findings in males with ADHD can be extrapolated to females with ADHD. In other words, parents need to be aware that some of the widely accepted information about ADHD may only apply to boys [22].

Recommendations for Clinicians Diagnosing and Treating ADHD

In practice, these findings of variable problems in ADHD participants urge clinicians to routinely test for cognitive strengths and weaknesses in all their ADHD clients in order to tailor interventions to the specific client profile. In other words, if, for example, working memory is a problem, then strategies that target such difficulties would be included, such as lists, mnemonics, and relying on other cognitive strengths. Other children may show specific deficits in processing speed, in which case, they may benefit from additional time in tests and taping lessons. At this point in time, assumptions cannot be made about which deficits will be present in which ADHD individual.

Recommendations for Parents Who Suspect Their Daughter May have ADHD:

  1. Get her properly assessed by someone who is aware of the way ADHD may manifests in girls – girls can often present as quiet daydreamers who don’t come to the attention of teachers. They can also have mood problems that mask the underlying symptoms of ADHD.
  2. If ADHD is confirmed, also ask for a “neurocognitive assessment.” A psychologist would be the best professional to conduct such an assessment. This type of testing would help determine whether she has specific problems that interfere with her learning, such as reading problems, poor memory, or slower than normal processing of information. This profile can then be used to modify her curriculum accordingly.
  3. Although medications can make a huge difference on the ADHD symptoms, they haven’t been found to help with academic problems. Consider other options to assist with the specific problems your child has – this might include psychotherapy to help with mood or anxiety, implementing behavioral management in the home and school, or receiving additional help with school-based problems.
References
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