Is it permissible to abandon prayer due to Attention-Deficit/Hyperactivity Disorder (ADHD), which leads to a distracted mind during it, and will a person afflicted with this disorder enter Paradise?

It is not permissible to abandon prayer for any reason. It is the second pillar of Islam and the pillar of the religion, and it does not cease to be obligatory for a Muslim as long as he is conscious. Severe warnings have been reported for those who neglect it. Therefore, absent-mindedness and lack of presence in prayer do not invalidate it. As for entering Paradise, its knowledge is with Allah alone, but we hope for it for the doers of good.