Antipsychotics can definitely be used to augment antidepressants. There are many antipsychotics that are good for mood stabilization.

Personally, I was on Wellbutrin and Lamictal for mood stabilization (Bipolar Disorder) and was still feeling significant depression. My PA at the time prescribed Latuda, which is the first antipsychotic I've ever been on, and it did wonders to help my depression.

If you're hesitant, it's good to talk with your doctor about the options and why they are thinking a certain medication. There is good evidence that augmenting can help. Antipsychotics are not without risks, though, so you want to make sure you go in fully informed.