The only "credit" for claiming a dependent over age 16 is $500. However, there are a few other things that might apply to claiming parents as a dependent.
If you pay medical expenses for a dependent, you can list those expenses as itemized deductions on your tax return.
If you provide care in your home for a dependent, and you have to pay for a caregiver to watch the dependent so you can work, you can claim the child and dependent care credit for the care expenses. Normally this credit is limited to children under age 13, but it also applies to adult dependents if they are disabled and unable physically or mentally to care for themselves.
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