The exact mechanisms by which ketamine works for depression are not yet fully understood. Ketamine is believed to work by blocking the action of a neurotransmitter called glutamate in certain parts of the brain, which can lead to increased levels of another neurotransmitter called brain-derived neurotrophic factor (BDNF). BDNF is thought to promote the growth and survival of neurons, which may help to reverse the effects of chronic stress on the brain and alleviate depression. Some researchers believe that depression may be related to inflammation in the brain, and that ketamine may have anti-inflammatory properties that can reduce inflammation and improve mood. Ketamine may also enhance the brain's ability to form new neural connections and pathways, which may help to reverse the effects of depression on the brain.