5 Barriers That Make Autism and ADHD Diagnostic Assessments Inaccessible—And What Clinicians Can Do About It

We talk often about the importance of accurate diagnosis for Autism and ADHD. But what’s discussed far less is how inaccessible the diagnostic process can be—particularly for those who need it most.

Whether it’s cost, cultural safety, long waitlists, or outdated frameworks, the barriers to assessment aren’t just frustrating—they’re often actively harmful. If we want our assessments to be ethical and effective, we need to interrogate the systems and practices that keep people out.

Here are five of the most common accessibility barriers in diagnostic assessment—and what we can do to address them in our clinical work. 1. Cost

Barrier: Comprehensive assessments are expensive. When they’re not publicly funded or covered by insurance, many individuals—especially those already facing financial hardship—simply can’t access them. This is deeply problematic, as formal diagnosis is often the gateway to support, funding, and reasonable adjustments.

What we can do:Keep the process lean—but still rigorous. Avoid adding high-cost components unless they’re truly necessary. For example, a WAIS is not essential for diagnosing adult ADHD and may inflate the cost without contributing to diagnostic clarity. Let’s be thoughtful about what we include—and why.

2. Waitlists

Barrier: Wait times of 6 to 18 months are now common. For someone already struggling, these delays can lead to worsening mental health, loss of trust in the system, or total disengagement.

What we can do: Be transparent about wait times. Support clients to make informed choices, and—if clinically appropriate—refer on to trusted colleagues who may have shorter waitlists. Ethical practice means putting the client’s access to care before our own caseload.

3. Medical Gaslighting and Limited Clinical Competence

Barrier: Many clients—especially those with internalised or masked presentations—are misdiagnosed, dismissed, or overlooked. There is a widespread lack of training in neurodiversity-affirming, contemporary models of assessment.

Even some experienced clinicians remain unfamiliar with current frameworks or don’t recognise how Autism or ADHD presents in adults, in marginalised groups, or in people who don’t "fit the mould." This is a specialised area of practice that requires skills well beyond standard university training.

What we can do:Engage in ongoing, high-quality professional development. Stay current with the literature, and regularly update your understanding of neurodivergent experiences. Reflect on the clinical models you were trained in—are they still serving the diverse presentations we now see? Are they inclusive? If not, it’s time to adapt.

4. Lack of Intersectional Awareness

Barrier: Assessments that ignore culture, trauma, gender identity, socioeconomic status, or co-occurring mental health concerns risk doing harm. Traits may be misinterpreted, overlooked, or pathologised in ways that erase someone’s full context.

What we can do:Adopt an intersectional lens throughout your entire assessment process. Ask: Whose experience was this tool designed around? Whose voice is missing from this process? And when you’re unsure—consult, seek supervision, or work in partnership with professionals from communities outside your own.

5. Rigid, Outdated Assessment Models

Barrier: Assessments that rely solely on structured observations, standardised tools, or deficit-based models often miss nuance—and alienate the person being assessed. For many neurodivergent clients, the process itself can be dysregulating or traumatic.

What we can do:Make your process collaborative. Ask the client what helps them feel safe. Offer flexible formats, breaks, and sensory accommodations. Use narrative-based tools and honour lived experience. A checklist alone doesn’t tell you what life feels like for your client—context always matters.

The Bottom Line

Improving accessibility in diagnostic assessment isn’t just a service upgrade—it’s an ethical imperative.

When we reduce barriers, we make space for more timely, accurate, and affirming diagnoses. And that kind of clarity can change lives—supporting identity, mental health, and long-term wellbeing.

Want to Learn More?

If you're ready to strengthen your diagnostic skills and deliver more neurodiversity-affirming assessments, my self-paced Autism & ADHD Diagnostic Training is designed for clinicians who want to do better.

In this training, you’ll learn all the essential skills for conducting diagnostic assessments for Autism and ADHD, including how to recognise and assess less stereotyped and more complex presentations.

📌 Learn more here.

Looking to save hours of time and strengthen your diagnostic process? Check out my Diagnostic Intake Questionnaires—designed to gather rich, relevant information before the interview even begins.