ADHD Clinical Outcome Scale – Self-Report (ACOS-Self)
A 15-item self-report measure of ADHD-related difficulties over the past two weeks.
Last reviewed: October 2026
- Full name
- ADHD Clinical Outcome Scale – Self-Report (ACOS-Self)
- Measures
- The ADHD Clinical Outcome Scale (ACOS) is a brief routine outcome measure for adult ADHD, developed by Adamis and colleagues (2024).
- Format
- 15 items · ~5 min · Self-report
- Score range
- 0 to 75
- Reliability
- Evidence here comes from the clinician-rated scale.
- Population
- Adults aged 18 and over.
- Interpretation
- 0–75No published severity bands
Scoring & Interpretation
The current ACOS-Self has 15 items rated from 0 to 5 over the past two weeks, giving a total from 0 to 75. No published severity bands or diagnostic cut-offs are applied. Read the individual difficulties alongside the total: the authors caution that a single overall total may not capture the different factors measured. Earlier ClientForms records used a different, withdrawn item set and must not be compared as the same measure.
| Score Range | Severity | Clinical Action |
|---|---|---|
| 0–75 | No published severity bands | Review item responses and clinical context; the total does not establish a diagnosis or severity category |
- Evidence here comes from the clinician-rated scale.
- Adamis and colleagues (2024) studied the clinician-rated ACOS in one adult ADHD clinic, with a comparison against patient self-ratings.
- That evidence should not be presented as a separate validation of the self-report form.
- The authors call for replication and caution about interpreting an overall total across different factors.
- No published severity bands or diagnostic cut-offs are applied here.
ClientForms publishes a standing audit of scoring and interpretation cut-offs across the whole catalogue: scoring accuracy audit.
When to Use This vs Alternatives
| Instrument | Measures | Items | Reach for it when |
|---|---|---|---|
| ACOS This page | ADHD-related difficulties over time | 15 | The comprehensive option you are reading about |
| ASRS | ADHD symptom frequency (screen) | 6–18 | You need to screen for adult ADHD at intake rather than track change over time. The ASRS is a WHO screening tool that flags whether ADHD is likely; the ACOS is an outcome measure for monitoring symptom severity once ADHD is being managed. |
| ADHD-FIS | Functional impact (screening) | 18 | You want a screening read on functional impact specifically rather than overall symptom severity. The ADHD-FIS (an original 18-item checklist) focuses on how symptoms affect daily life; the ACOS gives a broader symptom-and-impact total. |
| AQ-10 | Autistic traits (screen) | 10 | Autism is part of the differential. The AQ-10 screens for autistic traits, which the ACOS does not assess; use it where an autism question sits alongside ADHD. |
ADHD-related difficulties over time · 15 items
ADHD symptom frequency (screen) · 6–18 items
You need to screen for adult ADHD at intake rather than track change over time. The ASRS is a WHO screening tool that flags whether ADHD is likely; the ACOS is an outcome measure for monitoring symptom severity once ADHD is being managed.
Functional impact (screening) · 18 items
You want a screening read on functional impact specifically rather than overall symptom severity. The ADHD-FIS (an original 18-item checklist) focuses on how symptoms affect daily life; the ACOS gives a broader symptom-and-impact total.
Autistic traits (screen) · 10 items
Autism is part of the differential. The AQ-10 screens for autistic traits, which the ACOS does not assess; use it where an autism question sits alongside ADHD.
See It in Action
Sample: a completed ACOS, scored and interpreted.
How a completed ACOS scores and interprets:
Synthetic sample for illustration — not a real patient.
What It Measures
It has a clinician-rated form and a self-report form (ACOS-Self). Its 15 items cover the core symptoms of ADHD (attention and organisation, hyperactivity and impulsivity) together with common co-occurring difficulties and their impact on everyday functioning. It gives an overall severity score designed to track change over a course of care, not to establish a diagnosis.
When to Use the ACOS
Use the ACOS to monitor adult ADHD symptom severity over time, for example at baseline and again at review to see whether treatment is reducing symptoms and their day-to-day impact. It is an outcome measure, not a screening or diagnostic instrument: interpret the total in the context of a full assessment. The self-report form (ACOS-Self) is completed by the patient. ClientForms offers ACOS-Self; the clinician-rated version is not currently available here.
Who It's For
Adults aged 18 and over. Self-report: the patient completes the ACOS-Self. The clinician-rated version is a separate published form. The original study evaluated the clinician-rated scale in one adult ADHD clinic and compared it with patient ratings (Adamis et al., 2024). As a brief outcome measure it complements, rather than replaces, structured diagnostic assessment and clinical interview.
Frequently Asked Questions
What is the ACOS (ADHD Clinical Outcome Scale)?
The ACOS is a brief 15-item routine outcome measure of adult ADHD symptom severity, developed by Adamis and colleagues (2024). It has clinician-rated and self-report (ACOS-Self) forms and covers core ADHD symptoms together with common co-occurring difficulties. It is designed to track change, not to diagnose.
How is the ACOS scored?
The current self-report form has 15 items, each rated 0 to 5 for the past two weeks, and a total from 0 to 75. It has no published severity bands or diagnostic cut-offs. Read the item responses and clinical context alongside the total; the authors caution about a single total across different factors.
Is the ACOS a diagnostic test for ADHD?
No. The ACOS is an outcome and severity measure, not a diagnostic instrument. ADHD diagnosis relies on a structured assessment of DSM-5 criteria, developmental history and functional impairment; the ACOS helps monitor symptoms once that assessment is done, and the clinician owns the interpretation.
Where can I get the ACOS, and is it free to use?
The ACOS was published open access (Adamis et al., 2024, BJPsych Open) and is free to use with attribution for clinical practice and research. On ClientForms you send the ACOS-Self to a patient, who completes it on their phone, and the unbanded total and the item responses come back scored for you, ready to read or export.
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