Additionally: We know that if the full-time student child is 24 years or older at the end of the tax year, that immediately disqualifies them as a dependent. However, the parents can still pay loan interest, and claim the loan interest deduction for loans that originated when the child qualified as a dependent. See IRS Topic Number 456 - Student Loan Interest Deduction. Note the part about, "... or a person who was your dependent when you took out the loan..."
