Autism, ADHD, or Both? What a Thorough Differential Covers: A Guide for Understanding Neurodevelopmental Assessment

© 2024–2026 Raven LeFebvre. All rights reserved.

Written by: Raven LeFebvre, LCSW, LCSW-C, LICSW, MAC, CCTP-II

Owner and Founder, Silhouette Psychotherapy PLLC

Certified Clinical Trauma Professional Level 2 (CCTP-II)

PDA North America Level 1 Certified Clinician

Original Publication Date 10/23/2026

Copyright & Attribution Notice: © 2024–2026 Raven LeFebvre. All rights reserved. This publication, including its original text, selection, arrangement, and other original expressive content, is protected by applicable copyright law. You may cite or reference this publication with appropriate attribution where permitted by applicable law. Attribution alone, however, does not grant permission to copy, reproduce, distribute, display, publish, adapt, create derivative works from, or otherwise use copyrighted material beyond what is permitted by law. Except as permitted by applicable law, including fair use, please obtain prior written permission before reproducing, adapting, publishing, distributing, or otherwise using material from this publication. For permissions, licensing inquiries, or questions concerning use of this publication, please contact Silhouette Psychotherapy PLLC.

Raven's clinical practice is grounded in an anti-oppression and liberation-oriented therapeutic frame, recognizing that emotional, cognitive, and nervous system wellbeing cannot be understood apart from the social, relational, cultural, and systemic environments in which people live. This orientation emphasizes autonomy, self-determination, critical consciousness, and the right of clients to understand their experiences within the broader contexts of power, marginalization, identity, and relational conditioning. Her work considers how oppressive systems, interpersonal dynamics, internalized beliefs, and histories of adaptation can shape the ways people understand themselves and navigate relationships. She is collaborative, with intent to support greater agency, self-trust, authenticity, and freedom from patterns that require self-erasure in order to belong.

Autism, ADHD, or Both - AuDHD? What a Thorough Differential Covers: A Guide for Understanding Neurodevelopmental Assessment

If you're exploring whether you might be autistic, have ADHD, or both, you may feel uncertain about what that process actually involves. A thorough differential assessment is more than a checklist or a single conversation—it's a comprehensive exploration of how your brain works, how you've developed over time, and how you navigate the world. This document outlines what a careful differential assessment covers, so you can understand what to expect and what we're looking for together.

What Are We Assessing?

ADHD: Executive Function and Self-Regulation

ADHD (Attention-Deficit/Hyperactivity Disorder) involves differences in how your brain manages attention and focus, sustaining concentration, filtering distractions, and shifting attention when needed. It also affects executive function—planning, organizing, initiating tasks, and managing time. Impulse control is another key area, involving thinking before acting and managing emotional reactions. Working memory—holding and manipulating information in your mind—is often affected, as is emotional regulation, including managing frustration, disappointment, and intensity. It's important to understand that ADHD is not laziness, lack of intelligence, or a character flaw. It's a neurobiological difference in how your brain prioritizes and executes tasks.

Autism: Social Communication and Sensory Processing

Autism (Autism Spectrum Disorder) involves differences in social communication—understanding and using unwritten social rules, reading social cues, and interpreting tone and intent. It also affects sensory processing, including how you experience and respond to sounds, lights, textures, smells, tastes, and physical sensations. Your cognitive style—how you think, organize information, and approach problems—may be different, as may your behavioral patterns, including routines, repetitive behaviors (stimming), and need for predictability. Theory of mind, or understanding what others are thinking or feeling, can also be affected. Like ADHD, autism is not a social anxiety disorder, shyness, or a lack of empathy. It's a different neurotype with a distinct way of processing the world.

Why the Distinction Matters

While ADHD and autism can co-occur and may look similar on the surface, they require different strategies and support. ADHD support often focuses on structure, accountability, and external organization, while autism support often focuses on sensory accommodation, explicit communication, and acceptance of difference. Getting the differential right means you receive support that actually fits how you work.

What a Thorough Differential Assessment Covers

Developmental History

A comprehensive assessment always begins with your history, because both ADHD and autism are neurodevelopmental conditions—they've been part of how you work since childhood, even if you're only now recognizing them. We explore early childhood patterns, including whether you were an "easy" or "difficult" baby, how you played, and whether you preferred solitude or social interaction. Your school experience matters too—how you managed academically and socially, whether you struggled with attention, organization, or fitting in. We look at peer relationships, examining how friendships developed and whether you had difficulty understanding social rules or initiating friendships. Family patterns are important because these conditions often run in families. Your sensory history is explored, including whether you were sensitive to tags in clothing, loud noises, or certain textures as a child. We discuss special interests—whether you had intense, sustained interests and how you spent free time. Behavioral patterns are also examined, including whether you were restless, impulsive, or whether you needed routines and predictability. Why does this matter? ADHD and autism don't suddenly appear in adulthood. They're lifelong patterns. Understanding your childhood helps us see whether current struggles are recent or long-standing.

Current Functioning Across Contexts

How you function varies depending on your environment, stress level, and the demands placed on you. A thorough assessment looks at multiple areas of your life. In work or school settings, we examine how you manage deadlines and task initiation, whether you struggle with organization or time management, how you navigate workplace social dynamics, whether there are sensory challenges in your work environment, and whether you hyperfocus on certain projects. In relationships, we explore how you form and maintain friendships, whether you struggle with understanding others' expectations or feelings, how you communicate with partners or family, and whether social situations feel draining or energizing. At home and in daily life, we look at how organized your physical space is, whether you have routines that help you function, how you manage household tasks and responsibilities, and what sensory accommodations you need. Emotional regulation is also important—how quickly you become frustrated or overwhelmed, how you recover from emotional intensity, and whether you have difficulty reading your own emotional states. Finally, we assess sensory experience, including which sensory inputs bother you most, how sensory sensitivities affect your daily functioning, and what accommodations help you feel regulated.

Attention and Executive Function Assessment

This is where we look specifically at ADHD-related patterns. Regarding attention, we examine whether you can sustain attention on tasks that don't naturally interest you, whether you hyperfocus on topics of interest, how easily you are distracted, whether you lose track of time, and whether you can follow multi-step instructions. For executive function, we explore how you approach planning and organizing, whether you struggle with task initiation (knowing what to do but having difficulty starting), how you manage time and deadlines, whether you can break large projects into steps, and whether you procrastinate and what triggers it. Impulse control is assessed by looking at whether you act before thinking through consequences, whether you interrupt others or speak without filtering, whether you make impulsive purchases or decisions, and how you manage emotional reactions in the moment. Working memory is examined through questions about whether you forget what you were about to say mid-sentence, whether you struggle to hold multiple pieces of information in mind, and whether you need to write things down immediately or forget them.

Social Communication and Sensory Processing Assessment

This is where we look specifically at autism-related patterns. For social communication, we explore whether you find unwritten social rules confusing or exhausting to navigate, whether you struggle to read facial expressions, tone of voice, or body language, whether you prefer direct, literal communication, whether you find small talk difficult or draining, whether you have difficulty understanding others' perspectives or intentions, and whether you stim (rock, fidget, repeat words or phrases) when stressed or excited. Sensory processing is assessed by identifying which sensory inputs are most challenging (sounds, lights, textures, smells, tastes), how intensely you experience sensory input compared to others, whether certain sensory experiences cause physical pain or distress, whether you seek out certain sensory experiences (deep pressure, spinning, certain textures), and how sensory sensitivities affect your ability to function in different environments. Your cognitive style is explored through questions about whether you think in pictures, words, or patterns, whether you notice details others miss, whether you prefer to understand the "why" behind rules, and whether you think in literal or abstract terms. Behavioral patterns are examined, including whether you need routines and predictability, how you respond to unexpected changes, whether you have intense, sustained interests, and whether you engage in repetitive behaviors that feel calming.

Screening for Co-occurring Conditions

ADHD and autism don't exist in isolation. We also assess for anxiety disorders, which can mimic or co-occur with both conditions, depression, which can mask ADHD symptoms or compound autism-related challenges, trauma history, which can affect attention, emotional regulation, and social trust, learning disabilities, which often co-occur with neurodevelopmental conditions, sleep disorders, which significantly impact ADHD symptoms, and substance use patterns, which people with ADHD may use for self-regulation. Understanding what else is present helps us distinguish between symptoms caused by ADHD and autism versus other factors.

Standardized Assessment Tools

Beyond conversation, a thorough assessment typically includes validated questionnaires and rating scales. For ADHD, these might include the Adult ADHD Self-Report Scale (ASRS), Conners Rating Scales. For autism, common tools include the Autism Spectrum Quotient (AQ), Ritvo Autism Asperger's Diagnostic Index (RAADS-R), Social Responsiveness Scale (SRS), or the MIGDAS-2), which is considered the gold standard for neuro-affirming diagnostics. For both conditions, the BRIEF-A may be used to assess executive functioning . These tools provide objective data that complements clinical observation and self-report.

Differential Diagnosis Considerations

At Silhouette Psychotherapy we use an extensive psychometric battery of 35-45 instruments, alongside multiple in depth structured diagnostic interviews such as MIGDAS-2 and DIVA-5.

A thorough assessment explicitly considers what ADHD and autism are not. Several conditions can mimic ADHD, including anxiety disorders (which can cause racing thoughts and difficulty concentrating), sleep disorders (where fatigue mimics inattention), thyroid dysfunction or other medical conditions, depression (which can cause low motivation and poor concentration), and trauma responses (which can cause hypervigilance and difficulty focusing). Similarly, several conditions can mimic autism, including social anxiety disorder (difficulty in social situations), avoidant personality patterns (preference for solitude), trauma responses (hypervigilance and difficulty trusting), and obsessive-compulsive disorder (intense interests and repetitive behaviors). Why does this matter? It is paramount to work with an assessor who is experienced and skillful enough to parse apart what conditions might be mimics in order to prevent diagnostic overshadowing and to differentiate masking from internal experience, etc. A thorough differential ensures we're not missing something important.

Impact and Functional Impairment

Both ADHD and autism are only diagnosed if they cause genuine difficulty in your life. We assess how much these patterns interfere with work, school, or relationships, how much distress they cause you, what strategies you've already developed to manage, what areas of your life are most affected, and what would change if you had better support or understanding. This isn't about pathologizing difference—it's about recognizing when difference becomes burden and deserves support.

What Makes a Differential Assessment "Thorough"?

Time and Depth

A thorough assessment isn't rushed. It typically involves multiple sessions rather than a single appointment, detailed history-taking, observation across different contexts, completion of standardized measures, and collateral information from family members or friends either via psychometric screeners from an observer role and sometimes via interview.

Clinician Expertise

The clinician conducting the assessment should have training in neurodevelopmental disorders, understanding of how ADHD and autism present differently, awareness of how gender, culture, and trauma affect presentation, and knowledge of how these conditions present across the lifespan.

Consideration of Complexity

A thorough assessment recognizes that you might have both ADHD and autism, and that's not uncommon. Your presentation might be complicated by trauma, anxiety, or depression, and those need attention too. Your gender, race, and cultural background affect how symptoms show up, and diagnostic bias is real. You might be masking or camouflaging, appearing more "typical" than you actually are. Your symptoms might have changed over time—what was true in childhood might look different now.

After the Assessment—What Happens Next?

A thorough differential assessment results in clear findings about what the assessment suggests regarding your neurodevelopment, an explanation of how the clinician arrived at these conclusions, validation of your actual experience and strengths, specific recommendations for strategies, accommodations, and support tailored to your needs, and next steps, whether that's treatment, accommodation planning, or further evaluation. The goal isn't just a diagnosis. It's understanding yourself more deeply so that the support we develop actually works for you.

Questions to Bring to Your Assessment

As you prepare, consider reflecting on when you first noticed you were different from peers and what that was like. Think about what your biggest struggles are right now and how long they've been present. Consider what you do well and what comes naturally to you. Reflect on what sensory experiences bother you most and which ones help you feel regulated. Think about how you typically respond to change or unexpected situations. Consider what a "good day" looks like for you and what a difficult day looks like. Reflect on how you prefer to communicate—whether that's direct, indirect, written, or verbal. Think about what accommodations or strategies already help you. Consider whether there are family members with ADHD or autism and what you know about their experience. Finally, think about what would be different if you had better support or understanding around neurodevelopmental differences.

A thorough differential assessment is an investment in understanding yourself. It's not about finding a label for its own sake—it's about recognizing how your brain actually works so that the strategies, accommodations, and support we develop together are genuinely useful. The process takes time, depth, and expertise. And the result should be clarity, validation, and a clearer path forward. Bring your questions and reflections to our next session. This is collaborative work.

This document is meant to support your reflection. It's not a substitute for professional assessment or diagnosis.