In a recent paper, researchers described how they used a noncompetitive inhibitor of the NMDA receptor and partial dopamine receptor agonist, ketamine to rapidly reverse the symptoms of anhedonia in depressed patients. Ketamine has been featured on CBS news for its ability to quickly relieve depression unlike any other pharmacologic agent we have. It is typically used intravenously, and can cause hallucinations and dissociation (in fact it is also known as the club drug “Special K”). However, it seems to be able to reverse damage to the synapses caused by chronic stress, and relieve the symptoms of depression very quickly, within 30-40 minutes.
The down side to ketamine (besides lack of FDA approval for depression, the hallucinations, and lack of general availability) is that the effects don’t last. If you are lucky, you get a couple of weeks, then the depression comes back. Researchers and doctors, however, are hoping ketamine could be used as a bridging agent in seriously depressed, hospitalized patients, allowing them to feel better immediately while other, longer acting but much slower onset agents have a chance to get into the system and do their work. The immediate reversal of the key symptom of anhedonia [inability to experience pleasure] may be an even more important lesson we can learn from the use of ketamine.
The Ketamine Key: The horse tranquilizer helps depressed patients experience pleasure again