The use of subanesthetic ketamine infusions in treatment resistant depression and bipolar depression is becoming more common. Subanesthetic doses of ketamine cause the patient to dissociate, which was initially considered a side effect of this treatment; it is believed to play a role in a patient’s clinical improvement. Researchers attribute this result to an increase in brain-derived neurotrophic factor, a growth factor that stimulates the formation of new synaptic connections. Due to its psychogenic affect, ketamine treatment is less suitable for patients who experience mood disorders with psychotic features. Although symptomatic hallucinations seemingly conflict with the dissociative effects of ketamine, treatment of a patient with depressive type schizoaffective disorder revealed significant improvements in his depressive symptoms, demonstrating ketamine’s potential to be safely administered to patients with a variety of complex disorders.