I have an interesting theory about IBD and Depression.
We (Humans) have Serotonin receptors and the Colon actually helps produce and receive Serotonin which is very interesting as we do not have our colons, could we be lacking Serotonin? Or possibly less Serotonin Production and re-uptake. I take an SSRI (Lexapro) to combat this and it helps me tremendously.
The gut does way more than just digest food, anxiety, depression, can be linked to an imbalance of gut flora. Ever have that "feeling" in your stomach with Anxiety? That helps explain how our flora can effect our mental health as well. It's all about balance! Everyone thinks depression and anxiety is just the brain and that is false. I take Xanax for my anxiety (sparingly, as needed usually for panic attack or a to prevent a panic attack if I feel anxious) it's the only medication that helps my anxiety and I am very aware of its side effects and nature.
Breathing exercises, a good mindset, and exercise definitely help however personally I need meds to control my Anxiety/ Depression.