Summary of evidence review

The updated evidence review identified 15 studies that explored groups of people who were more likely than the general population to have ADHD or are more likely to have missed a diagnosis of ADHD. In children and adolescents, this included studies of anxiety disorders, autism spectrum disorder, epilepsy, family history of ADHD, imprisoned, intellectual disability, children in out-of-home care, mood disorders, oppositional defiant disorder, premature birth, substance use disorders, and tic disorders.

GRADE certainty of the evidence in the child and adolescent studies was very low for two areas, low in four areas, and moderate for six areas. Of the 12 different high-risk groups explored, eight had a significantly higher risk of having ADHD than the control groups (in order of risk):

1. People with autism spectrum disorder
2. Children in out-of-home care
3. People with epilepsy
4. People with intellectual disability
5. People with oppositional defiant disorders
6. People with anxiety disorders
7. People with preterm birth
8. People with tic disorders.

In adults, included studies explored nine different high-risk groups: people with borderline personality disorder, people with a family history of ADHD, people with Intermittent Explosive Disorder, people with internet addiction, people with psychotic disorders, people with substance use disorders, people who have made a suicide attempt, people with suicidal ideation, and people with treatment-resistant depression.

GRADE certainty of the evidence in the adult studies was low for eight high-risk groups and moderate for one.  Seven of the nine high-risk groups had a significantly higher risk of ADHD than the control groups (in order of risk):

1. People with Borderline Personality Disorder
2. People with internet addiction
3. People with psychotic disorders
4. People with substance use disorder
5. People with Intermittent Explosive Disorder
6. People with a family history of ADHD
7. People with suicidal ideation/behaviour.

Summary of narrative review

A systematic review and meta-analysis on the prevalence of ADHD in incarcerated individuals from 42 studies found 30% of youth and 26% of adults in prison had ADHD (Young, Moss, Sedgwick, Fridman, & Hodgkins, 2015b), echoed in a more recent review (Baggio et al., 2018). There is a high prevalence of ADHD in children and adolescents with mood disorders including bipolar and major depressive disorder (Sandstrom, Perroud, Alda, Uher, & Pavlova, 2021) and in adolescents with substance use (Lange, Rehm, Anagnostou, & Popova, 2018). Children and adolescents at higher risk of ADHD also include those with language disorders (Korrel, Mueller, Silk, Anderson, & Sciberras, 2017) and those with specific learning disorders (Boada, Willcutt, & Pennington, 2012; Morsanyi, van Bers, McCormack, & McGourty, 2018).

Around half of people with foetal alcohol spectrum disorder may have ADHD (Lange, Rehm, et al., 2018). People with acquired brain injury have higher rates of premorbid ADHD (Ilie et al., 2015). Low birth weight has also been associated with an increased risk of ADHD (Momany, Kamradt, & Nikolas, 2018). There also may be higher prevalence of ADHD in people with eating disorders such as binge eating disorders than that found in the general population (Wentz et al., 2005; Yates, Lund, Johnson, Mitchell, & McKee, 2009). Similarly, there is an increased risk of ADHD among people with sleep disorders (Cortese, Faraone, Konofal, & Lecendreux, 2009; Sedky, Bennett, & Carvalho, 2014), or problem gambling (Dowling et al., 2015).

Evidence also suggests that girls and women with ADHD may frequently go unrecognised or be diagnosed late (Hinshaw, Nguyen, O’Grady, & Rosenthal, 2021; Quinn & Madhoo, 2014), with a lower gender ratio in adulthood-diagnosed versus childhood-diagnosed ADHD (May, Aizenstros, & Aizenstros, 2021). This difference may be due to various factors including a low clinical suspicion for girls, in whom inattentive symptoms may be more prominent than hyperactivity-impulsivity symptoms (Quinn & Madhoo, 2014). Girls and women with ADHD may experience high levels of emotion dysregulation and sometimes receive other diagnoses such as anxiety and depression (Quinn & Madhoo, 2014).

Parents may under-recognise hyperactivity-impulsivity symptoms in girls, or a diagnosis might be made in girls only when other co-occurring emotional or externalising symptoms are present (Mowlem, Agnew-Blais, Taylor, & Asherson, 2019). The symptoms of ADHD may also vary during the menstrual cycle, and reproductive stages such as pregnancy and menopause (Haimov-Kochman & Berger, 2014; Roberts, Eisenlohr-Moul, & Martel, 2018), although evidence is currently limited (Camara, Padoin, & Bolea, 2021). This should be considered during the diagnosis and treatment of ADHD in women and girls.

Evidence-to-recommendation statement

The evidence-based recommendations were needed to raise awareness that the prevalence of ADHD is higher in some groups and to avoid health professionals missing a diagnosis of ADHD. Evidence was not identified in the evidence review for the groups indicated in recommendations by the hash symbol (#). However, the experience of the Guideline Development Group (GDG) and emerging research outlined in the narrative review, suggested that these groups experience a high prevalence of ADHD and can frequently be diagnosed late or have a missed diagnosis. These groups include girls and women, and the GDG agreed a specific recommendation is warranted to draw clinical attention to women and girls with ADHD.