Struggling with mood swings, anxiety, depression, lack of focus, or memory problems? The reason may not be related to your psyche. The root cause just might lie in your gut. What does your gut have to do with your mental health? A lot! Emotional and psychological pain—nervousness, sadness, stress, and grief—are often expressed with gut distress. Here’s how it happens.

Did you know that your gastrointestinal tract is lined with about 100 million neurons? That’s more neurons than you have in your spinal cord or in your peripheral nervous system, which is why the gut is often referred to as the “second brain.” This nerve tissue is in direct communication with the brain inside your skull, which explains why you get butterflies before a big job interview or feel queasy when you’re upset.