system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is it that a certain event can change our brain chemistry, such as giving us anxiety or other ailments. But we cant easily change it back?
gpt
There are a few major problems with fixing your brain chemistry:

1. It's easier to break something than to fix it. This is true of all things, not just brains, because there are more ways of being "broken" than there are of being "fixed." The human brain, being so delicate, is also prone to breaking more when you attempt something rather than getting better.
2. Brain chemistry is super complex and often involves a cascade of effects. Some of those effects can't just be undone. There's no such thing as the opposite of anxiety down at a chemical level, for example.
3. The side effects of your chemistry being broken - i.e. all the mental symptoms - often make your behavior change in such a way that you're prevented from recovering. This is partially why it's an *ailment* and not just a *mood,* after all.