Hi and thanks for the question!

I have been on two APs before and did not, at that time, experience any issues. I think it really depends on the combination. For example, two APs that cause drowsiness may have a compounded sedating effect.

As splitimage has said, the one drug (risperidone) has its benefits from helping the antidepressants and Seroquel has a good effect on anxiety because it happens to target both dopamine and serotonin receptors in the brain.

Splitimage has also raised a very good point- using two antipsychotics at once may be causing EPS, though a doctor would know for sure. It may also be the high dosages of each medication.
I was once on the Seroquel, as well as a typical antipsychotic, flupentixol. Seroquel was more for mood stabilising, but the flupentixol at low dosages acts as an antidepressant.

I'd say see how it goes and contact your doctor if anything comes up~
Good luck!