The Complete Neurodivergent Glossary

A full working dictionary of the autism, ADHD, and AuDHD landscape: the primary conditions, the conditions that commonly travel with them, the symptoms and traits, the movement vocabulary, the diagnostic models through history, and the actual criteria used to diagnose. Defined properly, without the watering down.

How to use this glossary

This is organised into seven parts: primary conditions, common co-occurring conditions, common symptoms and traits, industry terms, diagnostic models through history (newest to oldest), and the diagnostic criteria for ADHD and for autism. Listing a condition as co-occurring describes what frequently appears alongside autism and ADHD, not a claim that one causes another. No questionnaire or criteria list diagnoses anyone; assessment belongs with a trained clinician. Bookmark it and use it as a reference.

Understanding Neurodivergence: A Comprehensive Guide

Walk into any neurodivergent space, and the dialect hits immediately. Someone is in burnout because their spoons ran out while masking through a meltdown triggered by sensory overload. Their PDA is flaring, and the rejection sensitivity from a single unanswered text has eaten the afternoon. Every word there has a specific, defensible meaning. The trouble is that those meanings live scattered across clinical manuals, research papers, and a great deal of social media of wildly variable accuracy. What follows is the consolidated, fact-checked edition.

Part 1: Primary Conditions

Autism (Autism Spectrum Disorder, ASD)

Autism is a lifelong neurodevelopmental difference affecting social communication, sensory processing, and patterns of behaviour and interest. The term “spectrum” denotes a variety of presentations, not a line from “a little” to “a lot.” Unified as a single ASD diagnosis in the DSM-5 (2013), it absorbed several previously separate labels.

ADHD (Attention-Deficit/Hyperactivity Disorder)

ADHD is a neurodevelopmental condition involving differences in attention regulation, impulse control, and activity level. This condition is underpinned by executive function and dopamine-signalling differences. Recognised presentations are predominantly inattentive, predominantly hyperactive-impulsive, and combined. The name dates to 1987; the “deficit” framing is contested. Many describe it as dysregulation of attention rather than a shortage of it.

AuDHD

AuDHD is a community term, in wide use since the early 2020s, for being both autistic and ADHD. This is significant because the DSM-IV prohibited diagnosing the two together. Only with the DSM-5 in 2013 was simultaneous diagnosis permitted, leaving a generation only ever half-explained. The two conditions can pull in opposite directions, producing a distinctive internal experience rather than a simple sum.

Asperger’s Syndrome / Asperger’s Disorder

Asperger’s syndrome was a former diagnosis introduced in the DSM-IV (1994) for autistic people without language delay or intellectual disability. It was absorbed into Autism Spectrum Disorder in 2013. This label is now largely retired in clinical use, partly for consistency and partly because of the historical associations of its namesake. Some diagnosed under the old label still use it for themselves.

Pervasive Developmental Disorder (PDD) and PDD-NOS

PDD is an older diagnostic grouping that contained autism and related profiles. “Not Otherwise Specified” (added in 1987) captured presentations meeting some but not all criteria for autistic disorder. The whole grouping was superseded by the unified ASD diagnosis in 2013.

Part 2: Common Co-occurring Conditions

Co-occurrence is the rule, not the exception, in neurodivergence. The conditions below appear alongside autism and ADHD more often than chance would predict. That association is not the same as causation, and prevalence figures vary widely between studies.

Generalised Anxiety Disorder (GAD) and Autistic Anxiety

GAD involves excessive, persistent, hard-to-control worry. It is the most common co-occurring mental health difficulty in both conditions. “Autistic anxiety” names a related, often distinct experience: anxiety arising specifically from sensory load, social demand, uncertainty, and change, rather than free-floating worry.

Major Depressive Disorder (MDD) and Persistent Depressive Disorder (Dysthymia)

MDD is an episode of persistent low mood, loss of interest, and reduced function. Persistent depressive disorder (dysthymia) is a chronic, lower-grade form lasting two years or more. It is easily normalised as “just how I am,” especially when masking or alexithymia obscure it. Both are substantially elevated in neurodivergent people.

Obsessive-Compulsive Disorder (OCD) and Obsessive-Compulsive Personality Disorder (OCPD)

OCD pairs intrusive, unwanted thoughts (obsessions) with repetitive acts (compulsions) done to relieve anxiety. Its content is distressing and unwanted, which distinguishes it from enjoyable autistic routines and interests. OCPD is a pervasive preoccupation with order, perfectionism, and control experienced as part of one’s character rather than as intrusions. Both can be confused with autistic traits and require careful differentiation.

Complex PTSD (C-PTSD) and Developmental Trauma

C-PTSD arises from prolonged, repeated trauma and adds difficulties with emotional regulation, self-concept, and relationships to the core post-traumatic picture. Developmental trauma refers to adversity during childhood that shapes the developing nervous system. Neurodivergent people face elevated trauma exposure, including chronic invalidation and sensory adversity.

Borderline Personality Disorder (BPD) and Neurodivergent Misdiagnosis

BPD involves instability in emotions, relationships, and self-image. Autistic and ADHD people, particularly women, are sometimes given a BPD label when the fuller picture is neurodivergence plus trauma. The overlap is real and contested, which is precisely why informed, careful assessment matters.

Oppositional Defiant Disorder (ODD) and Misdiagnosed PDA

ODD is a childhood pattern of persistent irritability, argumentativeness, and defiance toward authority, co-occurring with ADHD at high rates. Some presentations labelled ODD are better understood as the anxiety-driven demand avoidance of a PDA profile. The drivers, and the support that helps, differ substantially.

Disruptive Mood Dysregulation Disorder (DMDD)

DMDD is a childhood diagnosis of chronic, severe irritability with frequent, intense temper outbursts disproportionate to the situation. It was introduced in the DSM-5 partly to curb over-diagnosis of paediatric bipolar disorder; it overlaps with ADHD emotional dysregulation.

Sensory Processing Disorder (SPD)

SPD is a proposed condition in which the brain has persistent difficulty receiving and responding to sensory information to a degree that disrupts daily life. It is not a standalone DSM diagnosis and is debated as a distinct entity, but a widely used clinical description. Sensory differences are formally recognised within autism.

Auditory Processing Disorder (APD)

APD involves difficulty processing the meaning of sound despite normal hearing. This includes trouble distinguishing speech from background noise, following rapid speech, or telling similar sounds apart. The ears work; the difficulty lies in how the brain decodes what they deliver.

Visual Processing Disorder (VPD)

VPD involves difficulty interpreting visual information despite normal eyesight. This includes problems with visual tracking, discrimination, spatial relationships, or making sense of complex visual scenes. It is the visual counterpart to auditory processing disorder.

Specific Learning Differences: Dyslexia, Dysgraphia, Dyscalculia

Dyslexia affects reading, spelling, and word processing. Dysgraphia affects handwriting, spelling, and getting thoughts onto the page. Dyscalculia affects number sense and arithmetic. All are independent of intelligence and commonly co-occur with ADHD.

Dyspraxia (Developmental Coordination Disorder, DCD)

Dyspraxia is a condition affecting motor coordination, planning, and execution of movement. It influences handwriting, balance, and everyday physical tasks. It co-occurs with autism and ADHD at strikingly high rates.

Tic Disorders and Tourette Syndrome

These are neurodevelopmental conditions involving involuntary movements and vocalisations (tics). They share fronto-striatal brain circuitry with ADHD and autism and co-occur with both well above chance.

Eating and Feeding Conditions (ARFID, Anorexia Nervosa, BED)

ARFID is restricted eating driven by sensory aversion, low interest, or fear, rather than body image. It is strongly linked to autistic sensory processing. Anorexia nervosa shows meaningful links to autistic traits and alexithymia. Binge eating disorder (recurrent loss-of-control eating) co-occurs with ADHD.

Sleep Architecture Disruption and Delayed Sleep-Phase Syndrome (DSPS)

Sleep architecture disruption alters the structure of sleep across the night. This includes the timing and proportion of deep and REM stages, which is why sleep can feel unrefreshing even at adequate length. DSPS is a circadian disorder in which the internal clock runs late, pushing natural sleep and wake times hours later than schedules demand. Both are common in ADHD and autism.

Insomnia and Obstructive Sleep Apnea (OSA)

Insomnia involves persistent difficulty falling or staying asleep, or waking unrefreshed. OSA is the repeated interruption of breathing during sleep from airway obstruction, fragmenting sleep and worsening daytime attention and mood. Both are worth ruling out, as their effects can mimic or compound ADHD.

Hypermobility, EDS, HSD, and Dysautonomia/POTS

Joint hypermobility, the Ehlers-Danlos Syndromes (especially the hypermobile type, hEDS), and Hypermobility Spectrum Disorder (HSD) involve connective tissue differences with pain and fatigue. They cluster with dysautonomia, dysfunction of the automatic nervous system, of which Postural Orthostatic Tachycardia Syndrome (POTS) is a common form causing dizziness and faintness on standing. The whole cluster is over-represented in neurodivergent people.

Mast Cell Activation Syndrome (MCAS)

MCAS is a condition in which mast cells release inflammatory mediators inappropriately, producing varied symptoms across multiple body systems. It is reported alongside the hypermobility-dysautonomia cluster that is over-represented in neurodivergence.

Irritable Bowel Syndrome (IBS) and Gut-Brain Axis Dysregulation

IBS is a functional gut disorder of pain, bloating, and altered bowel habit. The gut-brain axis refers to the two-way signalling between gut and brain. Its disruption is relevant to the high rates of digestive issues in neurodivergence and to the interaction between gut health, mood, and sensory experience.

Coeliac Disease and Non-Coeliac Gluten Sensitivity

Coeliac disease is an autoimmune reaction to gluten that damages the small intestine. Non-coeliac gluten sensitivity produces symptoms without that autoimmune damage. Both feature in discussions of neurodivergent gut health, though evidence for dietary links to neurodevelopmental symptoms specifically is mixed and frequently overstated.

Temporomandibular Joint (TMJ) Dysfunction

TMJ dysfunction involves pain and impaired movement of the jaw joint. It is associated with clenching, grinding, and connective tissue differences. It is reported more often alongside hypermobility and neurodivergence.

Functional Neurological Disorder (FND)

FND produces genuine neurological symptoms, such as movement, sensory, or seizure-like events. These arise from disrupted nervous-system functioning rather than structural damage. They are real and involuntary, not imagined.

Epilepsy and Seizure Disorders

These conditions involve recurrent seizures from abnormal electrical activity in the brain. Epilepsy co-occurs with autism at notably elevated rates compared with the general population.

LGBTQIA+ Intersectionality

Autistic and ADHD people are more likely than average to be transgender, non-binary, or otherwise gender-diverse, and to hold diverse sexual orientations. This intersection is well documented and deserves affirming, informed support.

Non-Verbal Learning Disability (NVLD)

NVLD is a profile of strong verbal skills alongside difficulties in visual-spatial reasoning, motor coordination, and social perception. It overlaps with, but is distinct from, autism.

Part 3: Common Symptoms and Traits

These are the lived features of autism and ADHD. Few people have all of them, and they vary in intensity and combination. This is why two people with the same diagnosis can look entirely different.

Executive Dysfunction

This is an impairment in the brain’s management system. It affects planning, prioritising, initiating, switching tasks, working memory, and impulse control. It is the core of ADHD and is present in autism too.

Working Memory Deficit

This refers to a reduced capacity to hold information “live” while using it. For example, you may forget why you walked into a room. This is a frequent feature of ADHD and a common reason instructions and intentions evaporate mid-task.

Task Initiation Difficulty

This is trouble starting a task even when the intention and desire are fully present. It is not laziness; the start button simply refuses to depress.

Task Switching Difficulty

This involves trouble disengaging from one activity and moving to another. Whether leaving an absorbing task or starting a different one, this overlaps with autistic inertia.

ADHD Paralysis State

This state occurs when someone feels so overwhelmed by tasks, choices, or information that the system freezes, and nothing starts at all. It is a gridlock, not a refusal.

Time Blindness

This is the difficulty in perceiving, estimating, and tracking the passage of time. It tends to exist as “now” and “not now.” This makes deadlines, durations, and punctuality perennial problems.

Hyperfocus

Hyperfocus is an intense, sustained absorption in an engaging task, common in ADHD. It can be highly productive and pleasurable, but it often leads to neglecting hunger, thirst, time, and obligations outside the task.

Autistic Inertia

This refers to difficulty starting, stopping, or transitioning between activities. A body at rest stays at rest; one in motion resists stopping, even when the activity should clearly end.

Object Permanence (Functional)

This is the colloquial “out of sight, out of mind” effect. For example, the friend not messaged, the leftovers forgotten, or the bill unseen behind another envelope. It is not the developmental concept of the same name.

Chronic Procrastination

This is the persistent delay of intended tasks driven by executive dysfunction, low task-related dopamine, and avoidance of discomfort. It is often paired with last-minute, deadline-fuelled bursts of activity.

Monotropism

This theory of autism (Murray, Lesser & Lawson, 2005) holds that autistic attention runs as a single powerful channel drawn deeply to a few interests at a time. This explains deep expertise, the pain of interruption, and flow states.

Hyper-Systemising

This is a strong drive to analyse, build, and understand rule-based systems. Proposed by Simon Baron-Cohen as part of his empathising-systemising theory of autism, it underlies deep pattern detection and structured expertise.

Weak Central Coherence

This proposed autistic cognitive style favours detail over the overall gist. The individual trees are in sharp focus while the shape of the wood arrives later. This is a strength for spotting errors and patterns.

Context Blindness

Peter Vermeulen’s concept describes reduced automatic use of context to interpret ambiguous information. This means that meaning is drawn more from explicit detail than from situational cues. It explains difficulty with sarcasm, idioms, and reading the room.

Bottom-Up and Top-Down Processing

Bottom-up processing builds understanding from individual details upward. Top-down processing starts from prior knowledge, context, and expectation. Autistic cognition often leans bottom-up and detail-first, which is why missing context can make a situation genuinely harder to read.

Cognitive Rigidity

This is the difficulty in shifting mental gears. It involves adjusting plans, switching strategies, or accommodating unexpected change. This is the cognitive root of distress when routines break without warning.

Linguistic Processing Delay

This refers to a lag between hearing or reading language and fully processing its meaning. Responses take longer to form. This is not a reflection of intelligence; the information is understood, just on a slightly delayed timer.

Hyperlexia

Hyperlexia is an advanced, often early, word-reading ability paired with comparatively weaker comprehension of meaning. This is sometimes seen in autistic children who decode text well before grasping the storyline.

Interoception

Interoception is the internal sense reporting on the body’s state. This includes hunger, thirst, temperature, heart rate, and the physical components of emotion. It is frequently muted or scrambled in neurodivergent people, which is how lunch goes missing until 4 PM and emotions arrive unlabelled.

Proprioception

This is the sense of where the body is in space, drawn from muscles and joints. Differences explain collisions with doorframes, misjudged distances, and a fondness for tight clothing and weighted blankets.

Vestibular System

The vestibular system is the balance and movement sense, based in the inner ear. It is the source of both motion sensitivity and the genuine regulation many people find in swinging, rocking, and spinning.

Sensory Seeking and Sensory Avoiding

These are two patterns from Dunn’s model. Seeking is actively pursuing sensory input (movement, pressure, sound, texture) because the nervous system registers it less readily or finds it regulating. Avoiding is actively reducing or escaping input because the nervous system registers it intensely. The same person can do both in different channels.

Hypersensitivity and Hyposensitivity

This refers to over- and under-responsiveness to sensory input. The same person can be hypersensitive in one channel (sound) and hyposensitive in another (pain). They can shift between them depending on context and load.

Habituation (and Its Absence)

Habituation is the normal process of tuning out constant or repeated stimuli. Autistic nervous systems often do not habituate well. This is why the fridge hum, the clock, or the clothing tag stays endlessly perceptible.

Stimming (Self-Stimulatory Behaviour)

Stimming involves repetitive movement or sound used to self-regulate. This includes rocking, hand-flapping, pacing, humming, fidgeting, and repeating words. It is a legitimate regulation tool, not a habit to suppress.

Sensory Overload

Sensory overload occurs when incoming sensory input exceeds the brain’s capacity to process it. This is distinct from distraction. Distraction is attention drifting; overload is the system flooding and the dials pinning to maximum.

Misophonia

Misophonia is a strong, often involuntary aversive reaction to specific sounds. This includes classical triggers like chewing, sniffing, or tapping. It is more than annoyance; the response is intense and physical, and it appears more often alongside neurodivergence.

Synaesthesia

Synaesthesia is a blending of the senses in which one input triggers another. For example, seeing colours when hearing music. This is more common among autistic people than in the general population.

Nervous System Dysregulation (Autonomic)

This state occurs when the autonomic nervous system, which runs heart rate, breathing, blood pressure, and the stress response without conscious input, sits in chronic activation. Many neurodivergent people live in a near-constant low-grade fight-flight-freeze state. This is because an environment full of sensory and social demand keeps registering as a threat. The result is hypervigilance, difficulty settling, fatigue, and a body that struggles to return to calm. This is distinct from diagnosable conditions such as POTS, though related; it is the everyday baseline dysregulation underneath.

Emotional Dysregulation

Emotional dysregulation involves difficulty managing the intensity and duration of emotional responses. These can arrive fast, large, and slow to subside. This is strongly linked in ADHD to executive dysfunction, with each feeding the other.

Rejection Sensitivity (RSD)

RSD is sudden, intense emotional pain triggered by perceived rejection, criticism, or failure. This is widely reported in ADHD. The rejection need not be real or intended to land like a physical blow.

Meltdown

A meltdown is an involuntary, outwardly directed response to overwhelm. This may involve crying, shouting, or loss of control over speech and movement. It is not a tantrum; there is no goal, no strategy, and no audience required.

Shutdown

Shutdown is the inward-directed counterpart to a meltdown. Speech, movement, and processing slow or stop as the system withdraws to protect itself. This can easily be mistaken for sulking or disengagement, which it is not.

Autistic Burnout

Autistic burnout is profound, chronic exhaustion, loss of skills, and reduced tolerance to stimuli. It is caused by prolonged demands exceeding capacity, classically from sustained masking. Recovery is measured in months or longer, not just a weekend.

Masking Fatigue

Masking fatigue is the accumulated exhaustion of sustained masking. This is the constant effort of monitoring and suppressing natural responses to appear neurotypical. It is a direct contributor to autistic burnout.

Alexithymia

Alexithymia comes from the Greek for “no words for emotion.” It refers to difficulty identifying and describing one’s own emotional states as they happen. It is found in roughly half of autistic people (Kinnaird et al., 2019) versus around 5 percent of the general population. This is a labelling problem, not an absence of feeling.

Prosopagnosia

Prosopagnosia is face blindness. It involves difficulty recognising faces, sometimes including familiar ones. This is reported more often by autistic people and is a frequent source of social misunderstanding.

Spoons

The term “spoons” comes from Christine Miserandino’s spoon theory (2003). It is a metaphor for finite daily energy. Each task costs spoons; when they are gone, willpower cannot conjure more.

Flow State

A flow state is complete, effortless absorption in an intrinsically rewarding activity. For monotropic minds, this is both a source of deep satisfaction and something whose interruption is genuinely painful.

Masking (Camouflaging) and Social Mimicry

Masking involves suppressing natural neurodivergent traits and performing neurotypical ones to fit in or stay safe. This includes copying others’ speech and mannerisms or rehearsing conversational scripts. It is effective for survival, costly to sustain, and strongly linked to burnout and late diagnosis, especially in women and girls.

Social-Emotional Reciprocity Differences

These differences occur in the back-and-forth of social interaction. This includes sharing interests and emotions, responding to others, and taking conversational turns. This is a core part of the autism criteria, reframed by the double empathy problem as a two-way mismatch rather than a one-sided deficit.

Non-Verbal Communication Differences

These differences occur in the use and reading of eye contact, gesture, facial expression, body language, and tone. This is a diagnostic feature of autism. Reduced eye contact or expression does not indicate reduced feeling or attention.

Info-Dumping

Info-dumping involves sharing detailed information about a subject of deep interest, often at length. This is frequently a sincere expression of enthusiasm and connection rather than a failure to read the room.

Parallel Play and Body Doubling

Parallel play is doing separate activities comfortably in one another’s company without direct interaction. Body doubling is completing a task in another’s presence because their company makes initiation and follow-through easier. Both are low-demand forms of genuine connection and support.

Selective Mutism

Selective mutism is an anxiety-based inability to speak in particular situations despite speaking freely in others. This is involuntary, not a choice, and is more common alongside autism and anxiety.

Echolalia

Echolalia involves repeating words, phrases, or sounds, either immediately or later. This can serve communication, processing, or self-regulation. It is a meaningful behaviour, not empty repetition.

Special Interest

A special interest is an intense, enduring, deeply rewarding area of focus. It is central to autistic cognition, regulation, and identity. This is qualitatively different from a clinical obsession because it is enjoyable rather than distressing.

Hyperfixation

Hyperfixation is an intense but typically temporary absorption in a topic, activity, or piece of media. This is especially associated with ADHD. It burns hot, then often moves on, unlike the enduring special interest.

Insistence on Sameness

This is a strong need for predictability in environment, routine, and expectation. It reduces the constant load of uncertainty. This is a diagnostic feature of autism; disruptions can be genuinely distressing.

Stereotyped or Repetitive Movements

These are repetitive motor movements, use of objects, or speech. This overlaps with stimming. “Stereotypy” is the clinical term; “stimming” is generally preferred in autistic self-description.

Need for Autonomy and Control

This is a strong drive to retain control over one’s own actions and resist external imposition. This is prominent in the PDA profile. It is often misread as defiance when it is an anxiety-driven need to feel in command of one’s circumstances.

Intolerance of Arbitrary Authority

This involves difficulty complying with rules or hierarchies that appear unjustified or inconsistent. However, individuals often readily accept requests that come with clear reasoning. This is related to demand avoidance and a strong sense of fairness, frequently mistaken for rebelliousness.

Demand Avoidance (The PDA Profile)

This is a proposed autism profile (Elizabeth Newson, 1980s) of extreme, anxiety-driven avoidance of everyday demands. This includes ones the person wants to meet, and even internal demands such as one’s own intentions. This is not in the DSM or ICD and is debated. Many prefer “persistent” over “pathological” and frame it around anxiety and autonomy rather than defiance.

Low Dopamine Baseline

This is a widely used model of ADHD proposing that the brain’s baseline dopamine signalling runs lower or less efficiently than typical. This is especially true in reward and motivation pathways. It offers an intuitive account of why routine tasks feel unrewarding while novel, urgent, or stimulating ones suddenly become possible. The fuller scientific picture is dysregulated rather than simply “low” dopamine. It involves differences in how dopamine is released, transported, and reabsorbed. However, the low-baseline framing captures the lived experience well.

ADHD-Specific Patterns

These include inattention (inconsistent attention regulation rather than simple inability to focus), hyperactivity (whether visible physical restlessness or an internal racing mind), impulsivity in action and speech, verbal hyperactivity (compulsive talking), dopamine seeking (a pull toward novelty, stimulation, urgency, and reward), novelty seeking, and historically described intrusive sleep (sudden overwhelming drowsiness when unstimulated).

Part 4: Industry Terms

This section covers the conceptual and movement vocabulary. These are the words used to talk about neurodivergence itself, rather than the conditions or symptoms.

Neurodivergent

This term refers to having a brain that develops or functions differently from the dominant societal standard. It is an umbrella term covering autism, ADHD, dyslexia, dyspraxia, Tourette syndrome, and more. This is a social and political category, not a clinical diagnosis.

Neurotypical

This term refers to having a brain that matches prevailing societal expectations of how thinking, attention, and social behaviour should work. It describes a majority, not a superior configuration.

Allistic

This term means not autistic. It is useful because “neurotypical” is too broad. An ADHDer is allistic but not neurotypical.

Neurodiversity

Neurodiversity refers to the simple fact that human brains vary. This is distinct from neurodivergence, which describes an individual.

The Neurodiversity Paradigm

This framework holds that neurological variation is a natural, valuable form of human diversity. It is not a set of deficits to be cured. It reframes conditions like autism and ADHD as differences requiring accommodation and acceptance.

Neuroaffirming Practices

These are approaches to support, therapy, and education that accept neurodivergent ways of being. They do not try to make people appear neurotypical. They prioritise wellbeing, self-understanding, and accommodation over the suppression of natural traits such as stimming.

The Autistic Spectrum

This describes autism as a range of presentations and support needs. It is not a single uniform condition or a linear scale from mild to severe. The term “spectrum” refers to the varied profile of traits, which differ in combination and intensity between individuals.

Atypical Neurodevelopment

This refers to the development of the brain and nervous system that follows a different trajectory from the statistical norm. This is the clinical framing underlying “neurodevelopmental condition.” Here, “atypical” means statistically less common, not defective.

Internalised Ableism

This term refers to the absorption of society’s negative attitudes about disability and neurodivergence into one’s own self-image. This produces shame, self-criticism, and the belief that one’s needs are illegitimate. It is a major, often invisible, barrier to self-acceptance and support.

Double Empathy Problem

This is Damian Milton’s (2012) reframing of autistic social difficulty as mutual rather than one-sided. Misunderstanding runs both ways across neurotypes. Autistic people often communicate easily with one another, and the breakdown occurs between groups, not within the autistic one.

Theory of Mind

This is the capacity to infer others’ thoughts, beliefs, and intentions. It has long been framed as an autistic deficit, but the double empathy problem reframes it as a two-way mismatch present in everyone to varying degrees.

Co-occurring / Comorbid

These terms refer to two or more conditions present in the same person. “Comorbid” is the clinical term; “co-occurring” is often preferred for carrying less implication of disease.

Diagnostic Overshadowing

This occurs when one prominent condition absorbs all clinical attention and masks another. This is the standard mechanism by which ADHD hides autism, autism hides ADHD, and either hides anxiety or depression.

Profile

This term refers to the specific pattern of strengths, difficulties, and traits in one individual. Two people with identical diagnoses can have completely different profiles.

Self-Diagnosis / Self-Identification

This refers to identifying with a condition based on research and self-observation, without (or before) formal assessment. This is widely regarded within the community as valid. Assessment costs can reach thousands, and waitlists often stretch years. This is distinct from a casual label adopted after a single video.

Part 5: Diagnostic Models Through History (Newest to Oldest)

This section covers the manuals and major instruments used to define and assess autism and ADHD, in reverse chronological order. The list doubles as a map of how the concepts themselves have shifted. Names appear, merge, and retire as understanding changes.

DSM-5-TR (2022)

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (American Psychiatric Association) is the current edition used predominantly in the United States and widely referenced internationally. The text revision updated wording and some criteria rather than overhauling the manual.

ICD-11 (2022)

The International Classification of Diseases, 11th Revision (World Health Organization) was adopted in 2019 and came into effect in 2022. This is the global standard for health classification, used across much of the world including Australia. It has its own criteria for autism and ADHD.

Conners 4 (2022)

This is the latest revision of the Conners rating scales. It assesses ADHD and related difficulties in children and adolescents via parent, teacher, and self-report.

MIGDAS-2 (2018)

The Monteiro Interview Guidelines for Diagnosing the Autism Spectrum, Second Edition (Marilyn Monteiro) is a sensory-based, narrative, relationship-led qualitative framework for autism assessment. It is valued for capturing presentations that more rigid tools can miss.

MONA (MIGDAS-2 Observation Narrative Assessment)

This is an observation-and-narrative assessment component within the MIGDAS approach. It focuses on building a qualitative descriptive picture of the person rather than a numeric score. It is part of the same sensory-based, narrative tradition as MIGDAS-2.

DSM-5 (2013)

The Fifth Edition of the DSM is the landmark edition that unified autism into a single Autism Spectrum Disorder. Crucially, it first permitted a simultaneous diagnosis of autism and ADHD.

ADOS-2 (2012)

The Autism Diagnostic Observation Schedule, Second Edition is a semi-structured, play- and task-based observational assessment administered by a trained clinician. It has long been regarded as a gold-standard component of autism assessment, designed to be combined with developmental history.

CARS-2 (2010)

The Childhood Autism Rating Scale, Second Edition is a clinician rating scale scoring observed behaviour against autism-related criteria to support diagnosis and gauge severity.

DSM-IV-TR (2000)

The text revision of the Fourth Edition maintained the DSM-IV categories (including separate Autistic Disorder, Asperger’s Disorder, and PDD-NOS) with updated supporting text.

ADOS-G (2000)

The Autism Diagnostic Observation Schedule, Generic is the version that introduced the modular structure spanning a broad developmental range. It is the direct ancestor of the ADOS-2. (The original ADOS, below, dates to 1989.)

ADI-R (1994)

The Autism Diagnostic Interview, Revised (Lord, Rutter & Le Couteur) is a detailed structured interview with a parent or caregiver about early development and current behaviour. It is often paired with the ADOS.

DSM-IV (1994)

The Fourth Edition introduced Asperger’s Disorder and placed autism within a set of pervasive developmental disorders. This is the edition whose rules prohibited diagnosing autism and ADHD together.

ICD-10 (1994)

The International Classification of Diseases, 10th Revision was endorsed in 1990 and widely implemented from 1994. This long-standing previous edition is still seen in older records and has now been succeeded by ICD-11.

ADOS (Original) (1989)

The Autism Diagnostic Observation Schedule (Lord et al.) is the first version of the now-standard observational assessment. It was initially for children with some expressive language.

ADI (Original) (1989)

The Autism Diagnostic Interview (Le Couteur et al.) is the original caregiver interview, later revised into the ADI-R in 1994.

DSM-III-R (1987)

The revised Third Edition renamed the autism diagnosis “Autistic Disorder.” It introduced PDD-NOS and renamed Attention Deficit Disorder to ADHD.

DSM-III (1980)

The Third Edition was the first to recognise autism as a distinct diagnosis (as “Infantile Autism,” under a new Pervasive Developmental Disorders category). It also introduced Attention Deficit Disorder (ADD).

CARS (Original) (1980)

The Childhood Autism Rating Scale (Schopler et al.) was one of the earliest standardised behavioural rating scales for autism. It was later revised into CARS-2.

DSM-II (1968)

The Second Edition predated autism as a separate category. Autistic children were generally classified under childhood schizophrenia.

DSM-I (1952)

The First Edition was the original American diagnostic manual. It contained no separate autism or ADHD diagnosis.

Beyond the manuals and the main diagnostic instruments above, several screening and assessment tools are in everyday use. For autism, these include the Social Communication Questionnaire (SCQ), the Autism-Spectrum Quotient (AQ, a self-report screen), the Ritvo Autism Asperger Diagnostic Scale-Revised (RAADS-R, an adult self-report), and the Camouflaging Autistic Traits Questionnaire (CAT-Q, which measures masking). There is also the Extreme Demand Avoidance Questionnaire (EDA-Q) for the contested PDA profile.

For ADHD, common instruments include the WHO Adult ADHD Self-Report Scale (ASRS), the Diagnostic Interview for ADHD in Adults (DIVA-5), the Vanderbilt and SNAP rating scales, the Wender Utah Rating Scale (WURS, a retrospective childhood self-report), the Weiss Functional Impairment Rating Scale (WFIRS, which measures real-world impairment rather than symptoms), and the Behavior Rating Inventory of Executive Function (BRIEF). Every one of these informs a clinician’s judgement; none is a diagnosis on its own.

Part 6: Diagnostic Criteria for ADHD

The criteria below summarise the current DSM-5-TR framework in plain language. They are paraphrased, not reproduced, and they are described for understanding, not for self-assessment. A diagnosis requires a qualified clinician weighing history, context, and alternative explanations.

Two Symptom Domains

ADHD is defined across two groups of symptoms. Inattention covers difficulty sustaining focus, careless errors, not seeming to listen, failing to finish tasks, disorganisation, avoiding sustained mental effort, losing things, distractibility, and forgetfulness. Hyperactivity-impulsivity covers fidgeting, leaving one’s seat, restlessness, difficulty being quiet, feeling “driven by a motor,” excessive talking, blurting answers, difficulty waiting turns, and interrupting.

How Many Symptoms, and for How Long

Each domain contains nine symptoms. Diagnosis generally requires at least six symptoms in a domain for children up to age 16, or at least five for adolescents of 17 and over and for adults. Symptoms must persist for at least six months to a degree that is inconsistent with developmental level and that disrupts daily functioning.

The Surrounding Conditions

Several symptoms must have been present before age 12. Symptoms must appear in two or more settings (such as home, school or work, and social life). There must be clear evidence they interfere with functioning, and they must not be better explained by another condition. Meeting the threshold in one domain but not the other determines the presentation.

The Three Presentations

There are three presentations: combined presentation (criteria met in both domains), predominantly inattentive presentation (inattention threshold met, hyperactivity-impulsivity not), and predominantly hyperactive-impulsive presentation (the reverse). Presentations can shift across the lifespan, and the inattentive presentation is a major reason ADHD is missed in those who are not visibly hyperactive.

Part 7: Diagnostic Criteria for Autism

As above, this is a plain-language paraphrase of the DSM-5-TR framework, offered for understanding rather than self-diagnosis. Autism is defined by two core areas, both of which must be present, alongside several surrounding conditions.

Criterion A: Social Communication and Interaction

There are persistent differences across multiple contexts in all three of the following: social-emotional reciprocity (the back-and-forth of conversation and shared emotion), non-verbal communication (eye contact, gesture, facial expression, body language), and developing, maintaining, and understanding relationships. All three must be present, though their expression varies enormously between individuals.

Criterion B: Restricted, Repetitive Patterns

At least two of four must be present: stereotyped or repetitive movements, use of objects, or speech; insistence on sameness, inflexible routines, or ritualised patterns; highly restricted, fixated interests of unusual intensity or focus; and hyper- or hyporeactivity to sensory input, or unusual interest in sensory aspects of the environment. The formal inclusion of sensory differences here arrived with the DSM-5 in 2013.

The Surrounding Conditions

Symptoms must be present in the early developmental period. However, they may not fully show until social demands exceed capacity, or they may be masked later in life. Symptoms must cause clinically significant impairment and must not be better explained by intellectual disability or global developmental delay, though these can co-occur.

Severity Levels

Both core areas are rated across three levels of support need: Level 1 (requiring support), Level 2 (requiring substantial support), and Level 3 (requiring very substantial support). The two areas are rated separately since a person can need very different levels of support for social communication versus restricted and repetitive behaviours. These levels describe support needs in context, not a person’s worth or capability.

Part 8: The Tests Used to Diagnose ADHD and Autism

There is no single blood test, brain scan, or one-off quiz that diagnoses either condition. Diagnosis is a process. A trained clinician combines questionnaires, structured interviews, developmental history, and direct observation, then weighs the result against alternative explanations. The instruments below are the tools that feed that judgement. Many begin as a screen that flags whether fuller assessment is warranted; none is a verdict on its own. This section lists the ADHD instruments first, then the autism ones.

Tests for ADHD

These split into self-report and informant rating scales, a structured clinical interview, measures of real-world functioning, and objective computerised attention tests.

ASRS (Adult ADHD Self-Report Scale)

A short self-report screening questionnaire from the World Health Organization. This is often the first step in adult ADHD assessment. It is a screen that signals whether to investigate further, not a diagnosis.

Appendix 2: Developmental History

A retrospective questionnaire for the individual being tested for ADHD. This accounts for ADHD symptoms and related information during their childhood. It is widely used in both clinics and research.

Childhood Behaviour Scale - Parent Report

A retrospective questionnaire for a parent to complete. This identifies if the individual being tested had ADHD symptoms during their childhood. It is widely used in both clinics and research.

Current Behaviour Scale - Self Report

A questionnaire for the individual being tested for ADHD. This accounts for ADHD symptoms and related information that is currently present. It is widely used in both clinics and research.

Current Behaviour Scale - Partner Report

A questionnaire for the individual’s partner to account for ADHD symptoms and related information that is currently present in the individual being tested for ADHD. This is widely used in both clinics and research.

Wender Utah Rating Scale

A retrospective self-report in which adults rate their own childhood behaviour. This is used to establish the childhood-onset element required for an adult ADHD diagnosis.

Diagnostic Interview

A structured clinical interview mapping symptoms against diagnostic criteria across both childhood and adulthood. This is a core instrument in formal adult assessment.

Weiss Functional Impairment Rating Scale

This measures real-world functional impairment across domains such as work, study, family, social life, and self-concept. It focuses on impairment, not just symptom count, which is central to diagnosis.

BRIEF-A (Behavior Rating Inventory of Executive Function)

This assesses everyday executive function, including planning, working memory, inhibition, and emotional control, in real-world settings. It complements symptom-focused measures.

Tests for Autism

These range from self-report and caregiver screening questionnaires to observational and interview-based instruments regarded as the diagnostic backbone.

DSM-5-TR

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (American Psychiatric Association, 2022) is the current edition of the manual used predominantly in the United States and widely referenced internationally. The text revision updated wording and some criteria rather than overhauling the manual.

CAT-Q (Camouflaging Autistic Traits Questionnaire)

This is a self-report measure of masking and camouflaging behaviour. It is valuable precisely because the people older criteria missed are often those who mask most effectively.

WHODAS 2.0 (WHO Disability Assessment Schedule 2.0)

This is a general measure of functioning and disability across six areas of daily life: understanding and communicating, getting around, self-care, getting along with people, life activities, and participation in society. It captures how much difficulty a person has functioning, independently of any particular diagnosis.

ABAS-3 (Adaptive Behavior Assessment System, Third Edition)

This questionnaire measures everyday adaptive skills across three domains: conceptual, social, and practical. It is used in autism and developmental assessment to capture real-world functioning rather than symptoms. This matters because capability on paper and capability in daily life can diverge sharply.

SRS-2 (Social Responsiveness Scale, Second Edition)

This questionnaire measures the social traits associated with autism. This includes social awareness, communication, motivation, and restricted or repetitive behaviour across the lifespan. It is used as both a screener and a measure of trait intensity.

BRIEF-A (Behavior Rating Inventory of Executive Function, Adult Version)

This is the adult counterpart of the BRIEF. It is a self-report and informant questionnaire assessing everyday executive function, including working memory, planning, inhibition, and emotional control, in real-world settings rather than in the artificial calm of a testing room.

Tests for Mental Health

DASS-21 (Depression Anxiety Stress Scales, 21-item)

This is a self-report questionnaire measuring three related states: depression, anxiety, and stress, over the past week. It is widely used to gauge current emotional distress and track it over time, not to diagnose. This is relevant given how often these states accompany neurodivergence.

Y-BOCS-SC (Yale-Brown Obsessive-Compulsive Scale, Symptom Checklist)

This is the checklist component of the Y-BOCS, used to identify the specific obsessions and compulsions a person experiences. It is helpful for separating genuine OCD, whose content is unwanted and distressing, from the wanted, enjoyable routines and interests of autism.

EAT-26 (Eating Attitudes Test, 26-item)

This is a widely used self-report screening questionnaire for attitudes and behaviours associated with eating disorders. It is a screen that flags risk and signals the need for fuller assessment, not a diagnosis in itself. It is worth pairing with awareness that ARFID, common in autism, is driven by sensory aversion rather than the body-image concerns this test centres on.

PCL-5 (PTSD Checklist for DSM-5)

This is a self-report measure of post-traumatic stress symptoms mapped to the DSM-5 criteria. It is used to screen for PTSD and to track symptom change over time.

ITQ (International Trauma Questionnaire)

This is a self-report measure based on the ICD-11. It is designed to distinguish PTSD from Complex PTSD (C-PTSD). This is notable because it captures the additional difficulties with emotional regulation, self-concept, and relationships that define the complex form. This pattern is more often relevant to neurodivergent people with prolonged adversity.

A label is the beginning of understanding, not the end of it.

Two cautions bear repeating. First, co-occurrence is not causation. That anxiety, POTS, or OCD appears more often alongside autism and ADHD does not mean any one produces another. The figures vary widely by study. Second, no list diagnoses anyone. The criteria and instruments here inform a trained clinician’s judgement; they are not verdicts to be self-administered from a page. Each term exists because a generation of people needed a word for something they had been living, unnamed, for years.

That is the real function of a reference like this one. Precision of language is what turns “I am lazy, broken, and too much” into “I experience autistic inertia, interoceptive hyposensitivity, and rejection sensitivity, and I run alongside anxiety.” Only one of those sentences describes a person you can actually support, and it is the longer, more accurate one.

Wired Differently Australia publishes educational content on neurodivergent experience. It is general information, not individual clinical guidance.