In recent years, awareness of adult autism diagnosis in Ireland has grown significantly. Alongside this has come a greater understanding of ADHD in adults — a condition that was historically under-diagnosed, particularly in women and girls.
What has also become increasingly clear is that autism and ADHD frequently co-occur. Research suggests that between 50 and 70 percent of autistic individuals also meet criteria for ADHD — a combination now widely referred to in the neurodiversity community as AuDHD.
This overlap creates very real challenges for clinicians, for individuals seeking assessment, and for the healthcare system as a whole. As a psychologist who regularly assesses adults for both conditions, I want to share how I approach the assessment process — and why getting the distinction right matters so much.
Why Adults Are Seeking Diagnoses Now
The rise in adult autism and ADHD diagnoses is not primarily explained by an epidemic. It reflects a long overdue broadening of clinical understanding. Until relatively recently, autism was widely conceptualised as a condition affecting young boys with very visible, significant support needs. Girls, women, and individuals with stronger masking abilities were routinely missed.
Similarly, ADHD in adults was poorly understood by many clinicians until the 1990s and 2000s brought a significant expansion in research. Many adults who struggled throughout school and their working lives with attention, organisation, impulsivity, and emotional regulation never received support because their difficulties were attributed to personality, laziness, or anxiety rather than a neurodevelopmental condition.
Today, many adults are coming to assessment after recognising themselves in accounts shared online by other late-diagnosed individuals, after a child of theirs receives a diagnosis, or after decades of unexplained difficulties finally prompted them to seek answers.
The Overlapping Symptoms of ADHD and Autism
One of the core reasons these two conditions are frequently confused — or one is missed entirely — is that they share many surface-level presentations:
- Difficulty with executive function (planning, organisation, time management)
- Social difficulties and challenges reading interpersonal situations
- Emotional dysregulation and intense emotional responses
- Sensory sensitivities
- Difficulty sustaining attention in low-interest tasks
- Impulsivity
- Sleep difficulties
- High anxiety levels
On initial presentation, it can be very difficult for both individuals and clinicians to determine which condition — or combination of conditions — is driving these experiences.
Key Distinctions Caroline Goldsmith Looks For
While the overlap is real, there are important clinical distinctions that experienced assessment reveals:
The nature of social difficulties: In ADHD, social difficulties typically arise from impulsivity — interrupting, speaking before thinking, missing conversational cues due to inattention. In autism, social difficulties more often reflect a fundamentally different way of processing social information and communication. Many autistic adults have developed sophisticated masking strategies that can make these differences less immediately apparent.
Restricted interests and routines: The intense, highly focused special interests characteristic of autism, and the strong preference for sameness and routine, are not core features of ADHD. Individuals with ADHD tend to experience rapidly shifting interests rather than deep, sustained focus in one area. Where a profound, specific special interest is present alongside other autism indicators, this is a significant clinical signal.
Sensory processing: Sensory sensitivities are a formal diagnostic criterion for autism and are present in the vast majority of autistic individuals. While some sensory sensitivity is seen in ADHD, the pattern, intensity, and pervasiveness of sensory processing differences in autism is typically distinct.
Developmental history: A detailed developmental history — covering early childhood communication, social development, language milestones, play patterns, and behavioural indicators — is essential in differentiating the two conditions. This is why the ADI-R (Autism Diagnostic Interview — Revised) forms a core part of my assessment process even for adults.
Response to masking and social exhaustion: Autistic adults, particularly those who have spent decades masking their autistic traits in social and professional contexts, frequently describe profound exhaustion — autistic burnout — following periods of sustained social effort. This pattern, while not exclusive to autism, is particularly characteristic and clinically significant.
The Dual Assessment: What It Involves
When an adult comes to ATC Ireland Psychology with concerns about possible ADHD, autism, or both, I conduct a comprehensive assessment that is designed to address all of these possibilities rather than narrowing prematurely.
This typically includes:
- A detailed clinical interview covering current difficulties, life history, and developmental history
- ADOS-2 assessment — the gold-standard observational assessment for autism
- ADI-R interview — developmental history and behavioural indicators
- ADHD-specific rating scales and self-report measures
- Executive function and attention testing where indicated
- Anxiety and mood screening (given high rates of co-occurring conditions)
The result is a comprehensive clinical picture that accurately identifies what is present, what is absent, and how different conditions may be interacting. Where both ADHD and autism are present, the report will reflect this — with recommendations tailored to the individual’s complete profile.
Why Getting the Diagnosis Right Matters
For adults who have spent years — or decades — without understanding why certain things are so much harder for them than for others, an accurate diagnosis is genuinely life-changing. It provides:
- A framework for understanding one’s own neurology and how it interacts with the world
- Access to appropriate therapeutic support and strategies
- Legal protection and reasonable accommodation rights in the workplace under Irish and EU equality legislation
- The ability to connect with others who share similar experiences
- Relief — often described by late-diagnosed individuals as the most significant and immediate benefit
Getting the right diagnosis with caroline goldsmit — not just any diagnosis — matters. Treating ADHD without recognising co-occurring autism, or vice versa, leads to incomplete support and can result in ongoing unnecessary struggle.
If you are an adult in Ireland who suspects you may be autistic, have ADHD, or both, I encourage you to seek a comprehensive assessment with a clinician experienced in both conditions. The ATC Ireland Psychology team is here to help.