Should I receive back pay for retroactive payments if I was put on SSI and then switched to SSDI as a Disabled Adult Child several years later?

Hi,

I can't really give you a good answer without additional information. You wouldn't have been eligible for disabled adult child's (DAC) benefits until a) one or both of your parents filed for their benefits or b) at least one of your parents died (https://www.ssa.gov/planners/disability/qualify.html#anchor8). Of course, the parent would also had to have worked and paid into Social Security long enough to be insured for benefits.

Assuming that you applied for DAC benefits when you were first eligible then it's unlikely that you would have been due any retroactive benefits. But, if you filed later or there was a delay in processing your claim and if your DAC rate is higher than was your SSI rate, then you may have been entitled to some back pay.

Best, Jerry