Weiss Functional Impairment Rating Scale
Parent Report (WFIRS-P)
Rate how your child's emotional or behavioural difficulties have affected each area of their life over the last month. This scale is used clinically by CAMHS and private practitioners to measure functional impairment and track whether treatment is making a real-world difference for your child.
This is not a diagnostic tool. The WFIRS-P measures how your child's difficulties are affecting their life, not whether they have ADHD or autism. Share your results with your child's clinician — they can use this to monitor progress and inform treatment decisions. No data is stored or sent anywhere.
About the WFIRS-P
The Weiss Functional Impairment Rating Scale — Parent Report was developed by Dr Margaret Danielle Weiss, MD PhD. It is completed by a parent or primary carer, rating how their child's emotional and behavioural difficulties affect family life, school, daily skills, and social participation.
The WFIRS-P is used by CAMHS services and private practitioners to assess functional impairment at assessment and to monitor the effect of treatment over time. It captures things symptom scales often miss — whether difficulties are affecting what your child can actually do and participate in. NICE NG87 — the national clinical guideline for ADHD — recommends that clinicians use standard rating scales to record symptoms and functional impairment at baseline and at each dose change (Recommendations 1.7.26 and 1.8.3). Completing this before an appointment gives your child's clinician a structured picture across all key areas of their life. See our NHS autism pathway and NHS ADHD pathway for information on assessment in Scotland.
Who should complete this? A parent, step-parent, foster carer, or other primary carer who lives with the child and can observe their day-to-day behaviour across settings. Rate based on your own observations — not what you think their teacher or others would say.
There is also a self-report version (WFIRS-S) for adults rating themselves.
WFIRS-P results
Items scored 2 (Often) or 3 (Very often) indicate areas of clinically significant difficulty. Print or save as PDF to share with your child's clinician.
| Domain | Items scored 2 or 3 | Total score | Mean score |
|---|
How to use these results
- Items scored 2 (Often) or 3 (Very often) indicate areas where your child's difficulties are causing clinically significant impairment.
- A higher mean score in a domain indicates greater overall difficulty in that area of your child's life.
- If your child is being treated for ADHD, repeat this scale at each review to track whether treatment is improving functional outcomes. Bring results to appointments.
- If your child is waiting for assessment, this can help you articulate to clinicians and to their school where the difficulties are having the greatest impact. Read our guide to the NHS autism pathway in Scotland or the NHS ADHD pathway.
- CAMHS is under significant pressure. If you are struggling while waiting, see our support resources or contact ADHD Scotland for advice.
Copyright and permission
The WFIRS-P is copyright © Margaret Danielle Weiss, MD PhD. It is reproduced here with the express written permission of Dr Weiss, granted 25 June 2026. The scale may be used by clinicians and researchers free of charge. Contact Dr Weiss at margaret.weiss@icloud.com for permissions.
Clinical reference: Weiss MD, Dickson R, Wasdell M, et al. Weiss Functional Impairment Rating Scale — Parent Report (WFIRS-P). American Psychiatric Association 158th Annual Meeting, Atlanta, GA; 2005.
See also: NHS Scotland Right Decisions — ADHD clinical guidance · RCPsych CR235 — ADHD in Adults (2023)