The last paragraph is noteworthy. Particularly the “However” and the “Additionally” parts:
The study makes an important contribution to the scientific understanding of psychological specificities of individuals with ADHD. However, it also has limitations that need to be considered. Notably, it was performed in one specific political situation and on members of a small homogenous national group. Additionally, all findings were based on self-reports. Studies on other cultures and using clinical diagnosis of ADHD might yield different results.