ADHD vs Anxiety in Adults: How to Tell the Difference

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

You’ve probably Googled it. Maybe late at night, after another day of scattered thoughts, unfinished tasks, and that low hum of worry that never quite goes away. The question that keeps coming up: Is this ADHD? Or is it anxiety? Or both?

You’re not alone. This is one of the most searched mental health questions on the internet, and for good reason. These two conditions share a surprising amount of overlap in how they look from the outside. Difficulty concentrating. Trouble finishing things. A mind that won’t sit still. The problem is, they feel different from the inside, they respond to different treatments, and mistaking one for the other (or missing the fact that both are present) can leave people stuck for years.

That’s where a thorough psychological evaluation becomes more than just a formality. It becomes necessary.

Why ADHD and Anxiety Symptoms Overlap So Often

Here’s something clinically important that often gets lost in the noise: one study suggests that up to 47% of adults with ADHD also meet criteria for an anxiety disorder (Kessler et al., 2006). That means if you have ADHD, there’s roughly a coin flip chance that anxiety is also in the picture. And when both are present, symptoms amplify each other in ways that make diagnosis genuinely complicated, even for experienced clinicians.

Anxiety can look like inattention. Racing thoughts, hypervigilance, rumination: all of these can tank your ability to concentrate just as effectively as ADHD does. At the same time, ADHD related executive dysfunction (the brain’s difficulty with planning, organizing, and following through) generates plenty of its own anxiety. Miss enough deadlines. Forget enough important things. You’d be anxious too.

To complicate matters further, emerging research suggests that anxiety may actually serve a compensatory function in some people with ADHD, particularly over time. A 2023 longitudinal study by Slomowitz and colleagues found that anxiety symptoms may buffer some of the inhibition weaknesses typically seen in ADHD, essentially acting as a kind of neurological alarm system that keeps people with ADHD from going completely off the rails. That’s a fascinating finding, but it also means that the person with ADHD and anxiety might actually look less impaired on certain tests than someone with ADHD alone, which makes the diagnostic picture even murkier.

The bottom line: this is not a simple checkbox exercise.

Why Self Diagnosis and Quick Screenings Fall Short

We live in an era of unprecedented ADHD awareness, which is largely a good thing. People are recognizing patterns in themselves that went unnoticed for decades. But awareness has also created a different problem: a significant number of adults are seeking (and receiving) ADHD diagnoses based on evaluations that simply don’t hold up to scrutiny.

Research published in The Clinical Neuropsychologist (Marshall, Hoelzle, & Nikolas, 2021) found that when evaluators relied only on a clinical interview and self report questionnaires without additional objective measures, a substantial portion of people who were not actually diagnosed with ADHD still would have been flagged as positive. Clinical interviews alone have high sensitivity (they catch most real cases) but poor specificity (they also catch a lot of cases that aren’t really ADHD). Self report scales have the same problem: they’re good at detecting something is off, but not great at telling you what.

That same body of research also found something humbling: experienced clinicians are often overconfident in their ability to detect symptom exaggeration or feigning. This isn’t a knock on clinicians. It’s a reminder that accurate diagnosis requires more than a good conversation. It requires a structured, multi method approach.

What a Comprehensive ADHD Evaluation Actually Includes

A well designed adult ADHD evaluation, one that can meaningfully differentiate ADHD from anxiety, depression, or their combination, should include several layers.

A Thorough Clinical and Developmental History

The clinical history is still the foundation. But “thorough” is doing real work in that sentence. We’re talking about a careful developmental history reaching back to childhood, because ADHD by definition begins early in life. We’re exploring how symptoms have shown up across different settings: school, home, relationships, work. We’re asking about family history (having a first degree relative with ADHD increases your own odds by roughly 3.5 to 5 times; Frazier & Youngstrom, 2006; Nikolas, Marshall, & Hoelzle, 2019). And we’re carefully mapping the timeline of anxiety symptoms relative to ADHD symptoms, because the sequence and context often tell us which came first.

Collateral Input from People Who Know You

Hearing from people who know you matters more than most people expect. Behavioral rating scales completed by a parent, partner, or someone who has known you for years add an outside perspective that is often more accurate than self report alone, particularly for childhood symptoms, which many adults struggle to recall accurately (Miller, Newcorn, & Halperin, 2010). Research suggests that parental ratings, in particular, are often better predictors of an ADHD diagnosis than the individual’s own recollections (Dvorsky et al., 2016). Having that corroborating voice in the room, so to speak, is not a nice to have. It’s genuinely important.

Neurocognitive Testing for Attention, Memory, and Executive Function

Neurocognitive testing adds a layer of objectivity that interviews and questionnaires simply can’t provide. Tests of sustained attention, working memory, processing speed, and response inhibition (the cognitive fingerprints of ADHD) give us something concrete to compare against normative data. No single test is diagnostic on its own, and it’s important to be clear eyed about that. The research shows that individual cognitive tests have modest effect sizes and that many adults with genuine ADHD will perform within normal limits on any given measure (Marshall et al., 2021). But a well selected battery, interpreted in the context of everything else we know, meaningfully sharpens diagnostic accuracy. Research combining behavioral rating scale data with cognitive test results has demonstrated substantially better specificity, meaning fewer false positives, than either approach alone.

Validity Measures to Ensure Accurate Results

A comprehensive evaluation also includes measures to assess the validity of symptom reporting and test effort. This isn’t about catching people in a lie. It’s about ensuring that the picture we’re getting is accurate, because both over reporting and under reporting can occur for all kinds of reasons, and a diagnosis built on invalid data doesn’t help anyone.

What Happens When ADHD or Anxiety Gets Misdiagnosed

If ADHD is missed, particularly in someone whose anxiety has been compensating for it all these years, that person may spend decades managing the wrong problem. Anxiety treatment helps, but it doesn’t address the underlying executive dysfunction. The relief is partial. The sense that something is still off persists.

If anxiety is missed because it’s attributed to ADHD, stimulant medication may feel like it’s not doing enough, or may actually worsen anxiety symptoms. Treatment stalls. Frustration builds.

And if neither is accurately identified, if a person walks out with a diagnosis based on a 20 minute conversation and a self report form, they may receive accommodations, prescriptions, or a narrative about themselves that isn’t quite right. That matters. The way we understand ourselves shapes how we approach our lives.

Getting the Right ADHD or Anxiety Diagnosis in Spokane

If you’re wondering whether ADHD, anxiety, or some combination of both is shaping your experience, a comprehensive psychological evaluation is the clearest path to an answer you can actually trust. Not because the process is infallible (it isn’t) but because a careful, multi method evaluation gives you the most complete picture currently available.

That picture has real value. It informs treatment decisions, helps you advocate for yourself, and often brings a kind of relief that comes from finally understanding why things have felt the way they’ve felt.

At Gerdin Psychological Services, psychological evaluations are built around exactly this kind of careful, individualized approach: taking the time to understand your history, gather perspectives from people who know you, and use objective measures to ground the clinical picture in data.

If you’d like to learn more or schedule a consultation, 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.