The use of pharmacogenomic testing has given mental health providers an additional tool to use when prescribing psychopharmacological treatment. Although useful, this technology has also presented many challenges in prescribing, specifically when treating individuals who have polymorphisms in the CYP2D6 pathway. During this presentation we will review pharmacogenomic testing and discuss challenging cases where polymorphisms in the CYP2D6 pathway have caused an increased difficulty when prescribing.