Imagine a lush green forest, filled with many trees with numerous branches. Now, imagine the opposite. The same trees, but instead brown and with branches falling off. These trees are now dying out. This forest is now sparse due to repeated fires, harsh weather, and pollution. The forest is functioning below what it could, and producing less oxygen and food for the creatures it protects.
Your brain is like a forest. Instead of trees, your forest is packed with neurons AKA brain cells. These brain cells have many connections, and create a vast network giving you the ability to breath, walk, and pretty much everything you do. Unfortunately, depression and chronic anxiety over time can reduce the number of neurons in your brain.
Not only are there less neurons, but the remaining neurons also lose connection between each other. This process, called dearborization, results in decreasing the brain cells’ ability to send electrical impulses to each other and effectively decreasing your brain’s ability to function, just like how fire and pollution affects a forest.
Understanding this structural change to the brain, it makes sense why ketamine is effective in treating depression and anxiety. Ketamine infusions increase expression of brain derived neurotrophic factor (BDNF). BDNF is a protein and has a role in normal brain function and plasticity. The brain is dynamic and ever changing, and BDNF gives the brain the ability to be flexible. BDNF helps restore what was structurally lost from the chronic effects of depression and anxiety. The regrowth and reconnection of neurons after ketamine infusions result in sustained improvement in depression and anxiety symptoms.
Given enough time your brain could return to its natural state on its own. You can probably think of examples in nature where the passage of time allowed for regeneration and regrowth. Ketamine is like using miracle-grow on your neural forest, speeding up the healing process and supporting you to return to a place where you have increased function and can even thrive.