ADHD- Athena Preprocessed Dataset Phenotype Classification

Dear All,
I am working the ADHD-Athena preprocessed dataset, i am confused the classification of DX in the phenotype csv file are more than one. Means, instead of only 0 and 1 values, 0 for healthy and 1 for ADHD, there are four labels 0, 1, 2, 3. What does it mean? Can anyone tell how could I differentiate between healthy and ADHD subjects only.

Thanks a lot.