Psychometric properties of the Sinhala version of the Swanson, Nolan, and Pelham rating scale (SNAP-IV) Parent Form in healthy children and children with ADHD.

OBJECTIVE

The present study aimed to translate and adapt the Parent Form of the MTA Version of the Swanson, Nolan, and Pelham ADHD/ODD rating scale (SNAP-IV) into Sinhala and examine its psychometric properties.

METHOD: The MTA version of the SNAP-IV was translated into the Sinhala language by adhering to the WHO translation and adaptational process. The final Sinhala SNAP-IV (S-SNAP-IV) was administered to parents of 412 healthy children and adolescents (age: 6-18 years), and 272 children and adolescents with ADHD (age: 4-19 years). Internal consistency and factor structure of the S-SNAP-IV were determined in each sample.

RESULTS

Conforming to that of the original English version, the S-SNAP-IV showed a three-factor structure (inattention, hyperactivity/impulsivity, and oppositional defiant disorder) in each sample, except for three item deviations (10,11, and 13) in the healthy sample. The S-SNAP-IV showed excellent internal consistency in the total sample (Cronbach's alpha = 0.97), healthy sample (Cronbach's alpha = 0.90), and the clinical sample (Cronbach's alpha = 0.94). The S-SNAP-IV also showed good discriminative validity: Only 1.5% of the healthy sample exceeded the cut-off scores in any domain, whereas all newly diagnosed, unmedicated children were S-SNAP-IV positive in at least one domain.

CONCLUSIONS

The findings suggest that the three-factor model fits the S-SNAP-IV, and it clearly distinguishes children with ADHD from non-ADHD children. We conclude that the S-SNAP-IV possesses satisfactory psychometric properties-consistent with the MTA English version and its translations into other languages-making it a reliable and valid instrument for screening children with ADHD.