My Son Is Nocturnal. Prozac Seemed To Have Helped But

My son is nocturnal. Prozac seemed to have helped but only for a while. He's 8. He was born with Zoloft in his system. He's on zoloft now and is back to being full blown nocturnal. School is underway and we're not getting anywhere. Can you recommend a prescription that I can ask his Dr to look into? He's also on quanfazine, 2 a night, they do not work at all. Can you please help?