ADHD Clinical Outcome Scale – Self Report (ACOS-SR)

Background / Development

Developed in 2024 by Adamis, Singh, Coada, Wrigley, Gavin, and McNicholas, the ADHD Clinical Outcome Scale (ACOS) was created to assess treatment response and functional outcomes in adults with Attention-Deficit/Hyperactivity Disorder (ADHD).

It builds on the clinician-rated ACOS and reflects the same theoretical foundation used in the Utah Criteria for adult ADHD, emphasizing both symptom control and day-to-day functioning.

Purpose / Intended Use

The ACOS-SR enables adults with ADHD to self-report on symptom frequency, emotional regulation, and executive functioning, alongside the impact these have on work, relationships, and daily life.

Unlike diagnostic screeners such as the ASRS or CAARS, it is intended for ongoing monitoring of individuals already diagnosed or receiving treatment.

It is most commonly administered at intake and at follow-up intervals to track treatment progress and real-world functional change.

Psychometric Properties

Initial validation data (Adamis et al., 2024, BJPsych Open) demonstrate strong reliability and validity for the clinician version, with equivalent structure expected for the self-report form.

• Internal consistency: α = 0.91
• Interrater reliability (clinician form): ICC = 0.91
• Construct validity: Correlated strongly with validated ADHD and functioning measures (e.g., WFIRS, ASRS)
• Responsiveness: Sensitive to treatment-related change over time

Further validation of the self-report version is underway, with early evidence suggesting comparable psychometric strength.

Structure and Content

The ACOS-SR includes 15 items, each rated on a 5-point Likert scale (0 = Not at all – 4 = Very much).

It covers five domains:

• Inattention and distractibility
• Disorganization and forgetfulness
• Impulsivity and restlessness
• Emotional regulation and frustration tolerance
• Functional impact in daily settings (work, home, relationships)

Items are phrased in plain, behaviour-based language for intuitive completion. Average completion time is 3–5 minutes, suitable for digital or in-person administration.

Scoring and Interpretation

Scores are calculated by summing all items (typical range 0–60 or 0–75 depending on scaling).

• Lower scores indicate reduced symptom burden and improved functioning.
• Stable or rising scores may reflect limited treatment response, adherence challenges, or emerging comorbidities.
• Reviewing domain-level trends supports individualized treatment planning.

Cut-off bands are under validation; interpretation should be clinical and comparative (change over time rather than absolute thresholds).

Clinical Application

The ACOS-SR is best used as a progress-monitoring tool in adult ADHD treatment or coaching contexts.

Recommended for administration every 4–6 weeks to document change in both symptom expression and functional recovery.

It pairs well with clinician-rated tools, structured interviews, or parallel outcome measures to provide a holistic picture of patient progress.

References / Sources

Adamis, D., Singh, J., Coada, I., Wrigley, M., Gavin, B., & McNicholas, F. (2024). Measuring clinical outcomes in adult ADHD clinics: Psychometrics of a new scale, the adult ADHD Clinical Outcome Scale. BJPsych Open, 10(6), e180. https://doi.org/10.1192/bjo.2024.739