A life course approach to understanding ADHD among women

Lead Research Organisation: Queen Mary University of London
Department Name: Sch of Biological & Behavioural Sciences

Abstract

For many years ADHD was thought of as a childhood disorder that mainly affected boys. However, we now know many adults have ADHD (about 2.5% of the population). Having ADHD in adulthood comes with higher risk for poor outcomes, including unemployment, substance abuse and even higher mortality. While in childhood more boys are diagnosed with ADHD than girls, in adulthood women make up 50% of the ADHD population. However, because of an outdated idea that ADHD only affects males, ADHD among adult women is largely ignored in research. This project seeks to address this neglect by investigating several important aspects of ADHD among women, including: (1) what features characterise girls who will later show ADHD in adulthood, (2) whether ADHD symptoms increase for some girls in adolescence, and (3) whether menstrual cycle hormonal changes make symptoms worse for women with ADHD.

Why are some women diagnosed with ADHD in adulthood without having a childhood diagnosis? We will investigate childhood and adolescent characteristics of girls who later go on to develop ADHD in adulthood using data from two large UK studies. We will consider several areas that might characterise these girls, including a more 'female' ADHD presentation (e.g. talkativeness rather than physical hyperactivity); compensation for ADHD symptoms (e.g. with pro-social behaviours) or family 'scaffolding' (e.g. intense parental involvement); and adolescent stressors (e.g. greater demands of more challenging schooling). If we identify earlier predictors of late-identified ADHD, this could have several impacts: first, this could help build more sensitive measures of ADHD to better capture girls who may 'fly under the radar' of teachers, parents and clinicians. This could in turn lead to earlier identification of ADHD, and limit the number of years girls and women with ADHD experience misdiagnosis and poor functioning.

Another reason women may be diagnosed with ADHD for the first time in adulthood could be that their ADHD got worse in adolescence. Adolescence is a key period of rapid brain development amidst increasing social and educational demands. Using data from a large study that follows adolescents from ages 9/10 to 12/13 and assesses ADHD symptoms each year, we will investigate whether some girls show a pattern of increasing ADHD symptoms in adolescence. We can also investigate what factors put some girls more at risk for increasing ADHD symptoms. Because this study also collected information on pubertal development and hormone levels, we can look specifically at whether the onset of puberty is associated with increasing ADHD symptoms. This is especially important as research shows that the age of pubertal onset is moving younger and younger among girls.

Among women with ADHD, the effects of hormones on functioning are a big concern. Many women with ADHD report their ADHD gets worse, or their medication doesn't work as well, at certain times of their menstrual cycle. However this has never been investigated in a research study. To look into this issue, we will collect information from women for 3 months in two ways: first, we will give women daily questionnaires on their smartphones about their ADHD symptoms, ADHD medication, menstrual cycle, and related problems (like low mood and cognitive problems). Second we will use a 'smart ring' device that women wear on their finger to sense sleep patterns and physical activity, which may help us understand how hormonal changes and ADHD are related. This 'smart ring' can also measure body temperature, which is important because body temperature changes over the menstrual cycle, so this is an innovative and non-intrusive way to assess phases of the cycle. Findings from this study could have a major impact on ADHD treatment for women, as cycle tracking, adjustments of medication dosage during certain cycle phases and interventions to support sleep and physical activity may be beneficial.

Technical Summary

For many years attention deficit hyperactivity disorder (ADHD) was thought of as a childhood disorder predominantly affecting boys; thus the majority of research has overlooked ADHD among girls and, to an even greater extent, ADHD among adult women. We now know ADHD can occur in adulthood at significant rates and is associated with a range of adverse outcomes, including unemployment, substance abuse, and even higher mortality. And while women are increasingly being diagnosed and treated for ADHD in clinical settings, research has not kept pace with this clinical change. This proposal will take a life course approach to provide important new evidence on risk factors and functioning among women with ADHD.

The gender ratio of ADHD diagnosis changes drastically across the life course, from a strong male predominance in childhood to nearly 1:1 in adulthood. However, why many women enter the ADHD population for the first time in adulthood is unknown. In Aim 1 we will investigate in two UK longitudinal cohorts what characterizes girls who will go on to exhibit ADHD in adulthood, examining whether they show a more 'female' ADHD presentation, compensation/scaffolding for their ADHD in childhood, and experience more adolescent stressors. In Aim 2, we will investigate whether some girls show increasing ADHD symptoms in adolescence, using data from a large longitudinal cohort with yearly assessments of ADHD. We will also assess whether the onset of puberty and associated hormonal changes are associated with increasing ADHD symptoms. In Aim 3, we will further investigate the role of hormones in ADHD in the first study to prospectively assess ADHD symptoms, impairment and associated functioning across the menstrual cycle among women with ADHD. In this remote monitoring study, we will measure body temperature, sleep and physical activity via passive monitoring on a 'smart ring' and assess women's symptoms and functioning via questionnaires on their smartphone.

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