Expert Advice Causes of Depression Gut Dysbiosis: Imbalance in gut bacteria is closely linked to mental health. Around 60% of feel-good neurotransmitters are produced in a healthy gut (explained in 4 Secrets to Feeling Good). GABA Depletion: Reduced levels of this calming neurotransmitter are also connected to gut health and mental wellness. Tryptophan and Serotonin […]