Purpose: Currently only one‐third of patients treated for depression enjoy complete remission of their negative symptoms. This paper explores ketamine research as it applies to understanding and treating mood illnesses. Conclusions: Ketamine's rapid antidepressant effect implicates downstream signal transduction involving the spontaneous transmissions associated with ketamine's action at the NMDA receptor. Practice Implications: Better understanding of brain neuropathophysiology offers hope for symptom relief to those living with affective illness refractory to currently available medical management. [ABSTRACT FROM AUTHOR]