Neurodevelopmental screening
SNAP-IV ADHD Rating Scale
The SNAP-IV (Swanson, Nolan, and Pelham) questionnaire assesses ADHD symptoms. Rate each behaviour over the last six months. Average scores help determine symptom clusters and whether follow-up evaluation is needed.
Inattention (Items 1–9)
Select how often each inattentive behaviour has occurred over the past 6 months.
1. Fails to give close attention to details or makes careless mistakes in schoolwork or chores.
2. Has difficulty sustaining attention in tasks or play activities.
3. Does not seem to listen when spoken to directly.
4. Does not follow through on instructions and fails to finish schoolwork or duties.
5. Has difficulty organizing tasks and activities.
6. Avoids or dislikes tasks that require sustained mental effort.
7. Loses things necessary for tasks or activities (e.g., toys, assignments, pencils).
8. Is easily distracted by extraneous stimuli.
9. Is often forgetful in daily activities.
Hyperactivity/Impulsivity (Items 10–18)
Rate the frequency of hyperactive and impulsive behaviours.
10. Fidgets with hands or feet or squirms in seat.
11. Leaves seat when remaining seated is expected.
12. Runs about or climbs excessively in inappropriate situations.
13. Has difficulty playing or engaging in leisure activities quietly.
14. Is “on the go” or often acts as if driven by a motor.
15. Talks excessively.
16. Blurts out answers before questions have been completed.
17. Has difficulty waiting for turn.
18. Interrupts or intrudes on others (e.g., butts into conversations or games).
Behaviour frequency is similar to peers. Continue routine monitoring if concerns persist.
Behaviour frequency is similar to peers. Continue routine monitoring if concerns persist.
Overall SNAP-IV average
0
Based on 18 items
Within expected rangeBehaviour frequency is similar to peers. Continue routine monitoring if concerns persist.
How to Use This Calculator
Collect observations
Gather input from parents, teachers, or self-report covering behaviour across settings.
Rate each symptom
Select a frequency score for every item. Missing responses reduce accuracy, so aim to complete all 18 items.
Review averages & plan follow-up
Scores ≥2 in either domain typically warrant further evaluation for ADHD and possible comorbidities.
Formula
- Assign numerical values to each response: 0 (Not at all) to 3 (Very much).
- Compute the average for inattention (items 1–9) and hyperactivity/impulsivity (items 10–18).
- Optional: average the two domain scores for an overall SNAP-IV average.
- Clinical cut-offs: average ≥2 suggests symptom cluster meets DSM-5 frequency threshold.
Full Description
The SNAP-IV is a widely used ADHD rating scale for children and adolescents. It aligns with DSM criteria and is suitable for parent and teacher reports. High scores help corroborate clinical impressions and track response to behavioural or pharmacological interventions.
Interpretation must consider developmental norms, cultural expectations, comorbid conditions, and functional impairment. ADHD cannot be diagnosed on rating scales alone—comprehensive assessment includes clinical interviews, collateral reports, academic review, and differential diagnosis for learning disorders, trauma, anxiety, sleep, or medical conditions.
Frequently Asked Questions
Can adults use the SNAP-IV?
Yes, though adult-specific rating scales (e.g., ASRS) may be more appropriate. Adapt wording for adult contexts.
How many raters are needed?
At minimum, obtain reports from two settings (e.g., home and school) to satisfy DSM-5 cross-situational criteria.
What about oppositional items?
Extended SNAP versions include oppositional defiant disorder items. This calculator focuses on the 18 ADHD core items.
How often should I repeat the scale?
Re-administer every 1–3 months during treatment, or at each medication adjustment, to monitor symptom change.