Table 1.

The criteria for classifying the possibility of ADHD in potential candidates

Possibility of ADHD	Before the age of 12	In adulthood
Class 1, compatible with ADHD	Three or more symptoms required for diagnosis; relevant evidence is obvious	Diagnostic criteria are met; there is no comorbidity; ADHD is clearly predominant even with the presence of comorbid disorder
Class 2, likely	At least three symptoms required for diagnosis are identified	There is a possibility of overlapping with other diagnosis, but predominant symptoms for ADHD are confirmed
Class 3, less likely	Diagnostic criteria are highly likely to be met, but there is insufficient data available to confirm	Difficult to distinguish from other diagnosis, but ADHD characteristics are clinically confirmed
Class 4, uncertain and deferred	Symptoms for diagnosis are less than three or there is insufficient data available to confirm	Difficult to determine the predominance between ADHD and comorbidity, and the influence of external factors such as environmental factors on the occurrence of symptoms cannot be ruled out
Class 5, not compatible with ADHD	Symptoms are not identified	Symptoms are very likely to be due to a condition other than ADHD or are within the normal developmental range