Autism and ADHD together

How often they overlap

Adult Autism Assessment Perth arranges autism and ADHD assessments for adults and adolescents across Perth and WA. Co-occurrence is common enough that assessing for one without considering the other is now poor practice. Until 2013 the diagnostic manual did not even permit both diagnoses in the same person, which is a large part of why so many adults hold only half of their answer.

What it looks like when both are present

People often describe a pull in two directions at once: a strong need for routine alongside an inability to stick to one; a deep interest that is genuinely absorbing until attention drops off a cliff; wanting order and being surrounded by mess. It is a common reason people conclude they are "not really either", because they do not match the tidy description of either on its own.

Why one hides the other

The traits can mask each other. Autistic structure and routine can compensate for ADHD disorganisation well enough that nobody notices the ADHD. ADHD sociability and impulsiveness can obscure autistic social difficulty. Treating one alone often produces a partial result and a lot of confusion about why it is only partial.

Why assess both at once

• The developmental history is largely shared, so together costs meaningfully less than two separate assessments.
• The differential matters. Several traits could belong to either, and deciding which requires looking at both at the same time.
• Treatment diverges sharply. ADHD may involve medication; autism does not. Getting the distinction right changes what happens next.

Where the traits pull against each other

This is the part adults describe most often, and it is why many conclude they are "not really either".

• Routine versus novelty. A deep need for predictability alongside an inability to sustain a routine once it stops being interesting.
• Deep focus versus no focus. Hours of complete absorption in an interest, and an inability to start a five-minute task that matters more.
• Order versus chaos. Wanting things a particular way and living surrounded by mess, which is experienced as a personal failing rather than a recognised pattern.
• Social exhaustion versus social impulsivity. Finding interaction costly and still interrupting, over-sharing or talking too long.

Neither diagnosis on its own accounts for that combination, which is exactly why assessing one and ignoring the other produces a partial answer.

Why one gets missed after the other is found

Once a clinician has an explanation that fits most of the evidence, the search tends to stop. An adult diagnosed with ADHD at 30 who is still struggling ten years later is frequently told to adjust medication, when the unexamined part is autism — and the reverse happens just as often.

A structured assessment that considers both from the start avoids paying twice and waiting twice.

What changes with a dual diagnosis

• Workplace adjustments differ. ADHD adjustments are typically about structure, deadlines and interruption; autistic adjustments about sensory environment, predictability and communication style. Most people need some of each.
• Treatment differs. ADHD may involve medication; autism does not.
• Self-understanding changes most of all, and this is what adults report mattering. Two partial explanations are harder to live with than one complete one.

Medication

ADHD medication in Australia is prescribed by a psychiatrist or, in some states, a paediatrician — not by a psychologist. A psychological assessment can identify ADHD and document it thoroughly, and prescribing is a separate step with a separate practitioner. Any service implying it can arrange medication directly is misleading you.