Traditionally, antidepressants are given for depression and antipsychotics are given for psychotic symptoms. But in the last few years I've seen adds on TV for Abilify to be given in addition to an antidepressant for depression. So an antipsychotic must apparently help some people with depression.
Welcome to the forum, Little-Loss-Soul, you ask a good question. I have always wondered why I take Lamotrigine when I take Risperidone and Bupropion. Asked my psychiatrist about it a while back, before he could answer, we got on a different topic. Best would be to ask your doctor.