Are there adverse effects between perphenazine and trazodone?

Yes. Both of these agents prolong the qtc interval and can result in life-threatening arrhythmias. Avoid the combo unless benefits outweigh the risks. There are other interactions as well, but this should be the one that you definitely know about.
Possibly. Per Drugs.Com drug interaction checker - trazodone plus perphenazine may ^ risk of arrythmia (especially if you have congenital long QT syndrome, electrolyte imbalances or other heart problems. )