Why do we respond the way we do when we are startled or scared? What does it mean that we wake in the night soaked with sweat and our heart racing? Why do I feel physically tense or nauseous at work?
Anyone who has experienced these uncomfortable moments knows how large of a role our bodies play in relation to our mental health. Here we have one of the oldest chicken and the egg questions in psychology: is what I am experiencing physically driving my mood and thinking, or is how I think and feel causing these sensations? The short answer is: YES. We are constantly riding a mutually reinforcing and dynamic pattern of experience. Interestingly, how we frame these experiences matters, especially with stress and anxiety. If we can pay close enough attention and be mindful of what we experience, we can even turn these to our advantage:
One of the quotes I often think of when I wonder about what I am experiencing is from John Tooby, a leading voice in evolutionary psychology:
"Modern skulls. Stone-age mind."
...meaning that while we live in the present, our neurology is adapted for the Paleolithic (and remains largely unchanged). So, the brain you are using is the same as folks who had "only" stone or wood tools and lived in small bands of hunter-gatherers. As sophisticated and modern as we think we are, we still rely on evolutionary strategies and responses that helped our ancestors live long enough to reproduce. What wasn't useful or best suited to its environment was slowly lost or culled.
Counterintuitively, this means that some of what we may consider disorders today may have had (or currently do have) some adaptive purpose. Said another way, you are wired for depression. And anxiety. And panic. And anger. You can thank your nervous ancestor who laid awake at night and was thus not picked off by a predator. Or another ancestor who was able to quickly increase their heart rate and respiratory capacity, resulting in their ability to protect their offspring from harm.
This does not mean that these feelings are pleasant. Or welcome. But they do serve a purpose.
However, when we experience these sensations - we must attend closely to what our bodies are telling us. What is your body preparing you for? If it is useful, great. Go with it. If it seems counterproductive, how can you channel these feelings and sensations into something that is more beneficial?
In many ways, psychology and the therapeutic process is about this process of understanding what evolution has given us to work with.