ADHD in Adolescence and Young Adulthood

ADHD in Adolescence and Young Adulthood: A Genetic and Genomic Perspective

By: Blanca Rebollo

ADHD Beyond Childhood

For many students, ADHD isn’t something left behind in childhood. It shows up in missed deadlines, chronic stress, and the constant feeling of working twice as hard to keep up. Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder marked by inattention, impulsivity, and hyperactivity, and it can affect far more than just school performance. It influences personal relationships, daily organization, motivation, and emotional regulation.

Here at Queen’s, data collected from wellbeing surveys suggest that roughly 1 in 10 attending students report a diagnosis of ADHD. In an environment with heavy course loads and tight deadlines, ADHD can quietly affect academic success. Unfortunately, these struggles are often misread as laziness or poor motivation rather than what they actually are: differences in how the brain regulates attention and executive function.

ADHD in Adolescents and Young Adults

Research consistently shows that most children diagnosed with ADHD continue to experience symptoms into their teenage years, and many into adulthood. Despite this, ADHD remains dramatically undiagnosed in adults and in university populations.

One reason for this gap is that ADHD symptoms in young adults often overlap with stress, anxiety, and burnout, all things that feel “normal” in university culture. As a result, ADHD can be misdiagnosed or overlooked entirely. Current diagnostic criteria were largely developed around children and don’t always reflect how ADHD presents later in life. This particularly applies to high-achieving students who have learned to mask their difficulties.

At the same time, ADHD diagnosis on campus presents a real challenge. Some students report self-reported symptoms that may not fully reflect a clinical ADHD presentation in order to access academic accommodations or stimulant medications believed to enhance performance. Studies show that students who overreport symptoms in self-initiated evaluations often fail more structured, clinical-led assessments.

As a result, clinicians must stay alert of university students without ADHD who request ADHD evaluation for the academic benefit it may entail. Self-reported ADHD symptoms can be easily exaggerated or fabricated, whereas procedures such as clinical interviews may make it easier to distinguish genuine ADHD presentations.

The Genetic Basis

ADHD is highly heritable. Rather than being caused by a single “ADHD gene”, the disorder is polygenic, involving hundreds of small genetic variations that influence brain development and function. Large genetic studies have identified several genes associated with ADHD, many of which are involved in brain connectivity, synapse formation, and neural signaling. For example, CHD13 codes for a calcium-dependent cell-cell adhesion protein that functions in neuronal development and synaptic plasticity. In a model mouse, the CHD13 gene was inactivated and showed evidence of hyperactivity and learning deficits (Drgonova J. et al, 2016).

Another well-studied gene, ADGRL3, plays a role in brain-specific signaling and cell adhesion. Loss of the gene leads to a reduction of dopaminergic neurons (critical for attention and motivation), hyperactivity, and impulsivity (Drgonova J. et al, 2016). Studying these genes helps researchers understand not just that ADHD is genetic, but how genetic differences shape brain circuits involved in attention and self-regulation.

Neurodevelopment During Adolescence

During adolescence, the brain undergoes maturation due to the increase of hormones during puberty. One of the last brain regions to fully mature is the prefrontal cortex, which governs executive functions like planning, organization, and time management. This region continues developing well into the mid-20s, the same age range as most university students.

ADHD is closely tied to differences in these executive control systems. Genetic variations that affect dopamine and norepinephrine signaling can alter how efficiently the prefrontal cortex develops. In practical terms, this means that students with ADHD are being asked to meet academic demands at a time when the brain systems required to manage them are still maturing.

ADHD in Student Populations

Over the past few decades, reported stress levels among university students have risen. ADHD is associated with higher risks of anxiety, depression, and mood disorders. As a result, many underdiagnosed students seek help for these disorders without realizing that untreated ADHD may be the driving force. Without addressing the root cause, treatment is often less effective.

Understanding ADHD at Queen’s and Beyond

Understanding ADHD as a neurodevelopmental and genetic condition rather than a lack of effort is crucial for creating supportive, inclusive academic environments. At Queen’s and beyond, recognizing how ADHD interacts with brain development and university life can help students access the understanding and resources they need to succeed.

Reference (APA):

Drgonova J;Walther D;Hartstein GL;Bukhari MO;Baumann MH;Katz J;Hall FS;Arnold ER;Flax S;Riley A;Rivero-Martin O;Lesch KP;Troncoso J;Ranscht B;Uhl GR; (n.d.). Cadherin 13: Human cis-regulation and selectively-altered addiction phenotypes and cerebral cortical dopamine in knockout mice. Molecular medicine (Cambridge, Mass.). https://pubmed.ncbi.nlm.nih.gov/27579475/