The SWAN captures variance at the negative and positive ends of the ADHD symptom dimension.
Arnett AB, Pennington BF, Friend A, Willcutt EG, Byrne B, Samuelsson S, Olson RK. The SWAN captures variance at the negative and positive ends of the ADHD symptom dimension. J Atten Disord. 2013 Feb; 17(2):152-62.