What does the expression “ADHD tax” mean? It refers to any monetary penalty that ADHDers are subjected to, due to the executive function issues that are part of ADHD. Here are some examples: Fees for late, or nonpayment, of bills Fees for overdue library books, rental cars, equipment, due to late return Higher interest rates for mortgages and loans, due to lower credit scores associated with late payments Larger credit card balances that cost more to pay off due to lack of sa