Your income from Social Security Disability Insurance (SSDI) and VA disability compensation is generally not subject to federal income tax, especially if these are your only sources of income. SSDI benefits are only partially taxable if your total income exceeds certain thresholds (for example, for a single filer, none are taxable if half your SSDI plus any other income is below $25,000), but with no other income, they typically remain nontaxable. Veterans disability benefits are ALWAYS tax-free.
As a result, you likely have no federal income tax liability to begin with, meaning your taxable income is already zero (or very low). The home mortgage interest deduction is an itemized deduction that reduces your taxable income on Schedule A of Form 1040, but it only provides a benefit if it lowers the amount of tax you will pay.
If there's no tax due, the deduction doesn't save you any money—similar to how someone with only nontaxable Social Security income wouldn't benefit from claiming mortgage interest.
You can still technically claim the deduction if you file a tax return and itemize (assuming you meet the other requirements, like the mortgage being secured debt on a qualified home), but it won't change your tax outcome since there's nothing to offset.
If you have any other income or specific circumstances (e.g., high SSDI amounts pushing part of it into taxable territory), it could be worth checking with a tax professional or using tax software to run the numbers. Also, note that this applies to federal taxes—state taxes might handle things differently depending on where you live.
