IMO It mostly likey will not have a significant effect other than significantly raised prolactin level and other steriod sides.
Lexipro being an SSRI, Risperdol being mainly a Dopamine antagonist as far as ive read. Risperdal in known to greatly increase prolactin and appearently it may cause prolactinoma, a benign tumor of the pituitary gland. But im no expert and i aints no doctor.
best of luck wit it
P.S. The best real advice i can offer is to research to understand what you are putting into your body and come a decision on your own(since its only yours to make) instead of subjecting your self to potentially faulty advice from a well meaning bro
