ADHD in College Students: Why So Many Get Diagnosed After High School

By Dr. Tyler Gerdin, PsyD, ABPP | Gerdin Psychological Services

Senior year of high school: two AP classes, varsity soccer, a part time job, and somehow a 3.5 GPA. . . with lots of parents’ help. First semester of college: one missed deadline became two, two became a pattern, the lectures blur together, and the student who was “fine” for twelve years of school is suddenly not fine at all. Then they are called into the Dean’s office to talk about academic probation. 

This is one of the most common stories I hear from college students, and from their parents. The question underneath it is almost always the same: Did something change? Or was something always there?

Almost always, the answer is: something was always there. College just removed the scaffolding.

Why College Exposes Undiagnosed ADHD

For many students with ADHD, diagnosed or not, high school is survivable because it comes with an enormous amount of external structure that most people don’t notice until it’s gone. A fixed schedule, six periods a day. Teachers who take attendance and follow up when assignments are missing. Parents who know what’s due when and ask about it at dinner. A social environment where everyone is going through the same routine at the same time.

ADHD, particularly the inattentive type, is fundamentally a disorder of self directed executive function. It’s not that people with ADHD can’t focus; it’s that their brain’s ability to regulate its own attention, initiate tasks without external prompts, manage time without external deadlines, and sustain effort without external accountability is significantly weaker than average (Dvorsky et al., 2019). High school, almost by design, provides all of those things externally. The student with undiagnosed ADHD borrows the structure of the environment without anyone realizing that’s what’s happening.

College strips that structure away. Suddenly there are three classes that meet twice a week, a syllabus handed out in August, no one checking whether the reading got done, and a residence hall full of interesting distractions at every hour of the day and night. For a student whose brain has been quietly relying on external scaffolding for years, this is not just an adjustment. It’s a system failure, and it often hits within the first semester.

How ADHD Affects Academic Performance in College

Estimates of ADHD prevalence among college students range from roughly 2 to 12%, depending on the criteria and methods used, with many researchers noting that the condition is meaningfully underdiagnosed in this population (Nugent et al., 2014; Sedgwick, 2017). What the research is consistent about is the academic impact when ADHD goes unaddressed.

College students with ADHD show lower GPAs, higher rates of course withdrawal, more academic probation, and lower graduation rates than peers, even when they’re putting in comparable or greater hours of study time (Heiligenstein et al., 1999; DuPaul et al., 2021; Pagespetit et al., 2024). That last detail is clinically important: this is not a motivation or effort problem. It’s an efficiency and executive function problem. A student with ADHD may study twice as long as a classmate and retain half as much, not because they’re not trying, but because sustained, self directed cognitive effort is the specific thing their brain struggles to regulate.

Inattention symptoms, in particular, are the strongest predictors of long term academic underperformance in college, more so than hyperactivity or impulsivity (Henning et al., 2021). The student who is quietly drifting through lectures, losing track of reading, and starting papers at midnight the night before the deadline, not because they don’t care, but because the initiation system in their brain simply won’t fire until the deadline itself creates enough urgency, is the student most at risk and most often missed.

Why ADHD Goes Undiagnosed Through High School

A significant portion of students who arrive at college with ADHD have never been formally evaluated. Some managed well enough in a structured environment that no one ever raised a flag. Some were identified as “bright but underperforming” without anyone asking whether there was a neurological reason for the gap. Some, particularly women, as discussed in an earlier post in this series, were described as anxious, daydreamy, or perfectionistic, and the ADHD underneath went unrecognized. Don’t forget that many parents cannot withstand the urge to help their kids keep grades up, run forgotten assignments to school, and help proof read papers.

The college environment is often the first context demanding enough to make the underlying differences impossible to compensate for. Qualitative research with college students and even medical students describes a common pattern: they knew something was always harder for them, but they didn’t have a framework for it, and it wasn’t until the demands peaked and mental health began deteriorating that they sought evaluation (Kwon et al., 2018; Godfrey-Harris et al., 2023).

That’s a long time to wait. And the longer the wait, the more a student has likely internalized the wrong explanation for their struggles, that they’re lazy, disorganized, not cut out for this level of work, when the accurate explanation is neurobiological and addressable.

Executive Function Deficits and Why They Matter More Than Symptom Counts

Research consistently finds that executive function deficits, not just ADHD symptom counts, are the strongest predictors of academic impairment in college students with ADHD (Dvorsky et al., 2019; Gray et al., 2016). Specifically, self motivation, planning, and organization predict GPA and overall functioning beyond what raw attention symptoms alone would predict.

This matters for intervention. Medication helps, and the research supports its use for eligible students, but medication alone doesn’t teach a student how to organize a semester’s worth of assignments, break a large project into manageable pieces, or recognize that “I’ll do it later” is a pattern, not a plan. Executive function coaching, academic support services, and the accommodations available through disability services all address different pieces of the picture. Getting the formal documentation needed to access those services is where a comprehensive evaluation becomes practically essential.

What an ADHD Evaluation Provides for College Students

For a college student with ADHD, a comprehensive evaluation does several things simultaneously. It establishes whether ADHD is actually present, which requires more than a self report questionnaire, and involves a developmental history, behavioral rating scales completed by multiple informants, and often cognitive testing that captures executive function and attention directly (Reilley, 2005; Sedgwick-Müller et al., 2022). It rules out or identifies co-occurring conditions, anxiety, depression, a learning disability, that may be contributing to academic difficulties alongside or instead of ADHD. And it produces the kind of formal, clinically grounded documentation that disability services offices require to authorize accommodations.

Those accommodations, extended time, distraction reduced testing environments, note taking support, deadline flexibility, are not advantages. They are adjustments that correct for a neurological difference in a setting that was designed for people without that difference. A student who needs twice as long to complete a timed exam because their processing speed is significantly lower than their reasoning ability is not being given an edge. They’re being given an even playing field.

Getting that documentation right matters. Disability services offices at colleges and universities have specific requirements for what evaluations need to include, and a well conducted, comprehensive evaluation produces a report that holds up to that scrutiny and provides the specific data those offices need to approve support.

And no, these accommodations do not represent an unfair advantage over others. They are simply ways to level the playing field. Studies show that when people receive accommodations who don’t have ADHD or need them (including medication), grades generally do not improve. 

ADHD Testing for College Students in Spokane

If you’re a college student who has always worked harder than it seems like you should have to for the output you’re getting, if the structure of high school kept things manageable and the freedom of college has not been the gift it was supposed to be, an evaluation is worth pursuing. Not because struggle means something is permanently wrong with you, but because understanding how your brain actually works is the foundation for building the kind of structure and support that works with your neurology rather than against it.

If you’re a parent watching this happen from a distance and not sure how to help: a comprehensive evaluation is concrete, actionable, and often the clearest path forward.

At Gerdin Psychological Services, ADHD evaluations for college students and young adults are a core part of our work, including the documentation needed to support accommodation requests. Reach out at drgerdin@gerdinpsych.com or 509-676-4313.

Dr. Tyler Gerdin, PsyD, ABPP is a board certified clinical psychologist in Spokane, Washington, specializing in psychological and neuropsychological assessment for neurodivergent teens and adults