I ran a check on the ones you listed and came up with the
interaction between
Cymbalta and trazodone - it says there is an increased risk of serotonin syndorme.
Some of the symptoms of serotonin syndrome are:
Cognitive effects: headache, agitation, hypomania, mental confusion, hallucinations, coma
Autonomic effects: shivering, sweating, hyperthermia, hypertension, tachycardia, nausea, diarrhea.
Somatic effects: myoclonus (muscle twitching), hyperreflexia (manifested by clonus), tremor.