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

Foundational Context

The ADHD Clinical Outcome Scale (ACOS) was developed by Adamis and colleagues (2024) to address a practical gap: adult ADHD clinics needed a brief, repeatable way to measure clinical outcomes that captures not just core symptoms but the comorbidities and functional difficulties that commonly accompany adult ADHD. Earlier outcome work in these services relied mainly on functional or quality-of-life scales.

The ACOS is clinician-rated, and the authors also evaluated a modified version completed by the patient — the self-report form referred to here as the ACOS-SR. Comparing the two gives clinicians both an independent rating and the patient's own perspective on their functioning.

What the Assessment Measures

Factor analysis of the ACOS identified four areas:

• Attentional and organizational problems — sustaining focus, distractibility, planning, and task follow-through
• Hyperactivity and impulsivity — restlessness and acting without reflection
• Comorbidities — co-occurring clinical problems that frequently accompany adult ADHD
• Substance use, self-harm, and relationships — alcohol or drug use, self-harm, and tension in close relationships

The 15 items are rated on a Likert scale. Including typically co-occurring clinical domains is what makes the scale suited to repeated use at routine clinic contacts.

Interpretation Guidelines

• The ACOS-SR is an outcome-monitoring measure, not a diagnostic tool.
• As a recently published scale (2024), it does not yet have widely established total-score cut-offs; tracking change over time is more informative than any single score.
• The clinician-rated and self-report versions can diverge — the patient's perspective (ACOS-SR) is a complement to, not a replacement for, the clinical rating.
• When ADHD is being assessed for the first time, pair the ACOS-SR with diagnostic tools and a full clinical evaluation.

Psychometric Properties

In the initial validation (148 adults attending an ADHD clinic; mean age 30.1):

• Interrater reliability between two clinicians was high (r = 0.868).
• Agreement between the patient and clinician versions was moderate (r = 0.663).
• Internal consistency was good (intraclass correlation coefficient = 0.829).
• Concurrent validity was supported by correlations with the Adult ADHD Quality of Life Questionnaire (AAQoL, r = −0.573) and the Weiss Functional Impairment Rating Scale (WFIRS, r = 0.477).

The authors describe the psychometrics as promising and the scale as suitable for clinician-rated outcome monitoring at every patient contact.

Limitations

• Not a diagnostic assessment.
• A recently published scale with a smaller evidence base than long-established measures such as the ASRS.
• Should be interpreted alongside other clinical information, not in isolation.