Try to figure out if your depression is caused by deficiencies in things like amino acids and neurotransmitter precursors due to malabsorption problems from gut dysbiosis before you run off to the nearest shrink to be prescribed pills that have severe side effects instead of what you really need. I found this example of how the state of your guts can cause depression. I think it is very nicely explained. At the very basic level, our body is all about chemistry. Digestion, respiration, central and peripheral nervous system and the endocrine system all function based on chemistry. In order to function properly, the body requires a huge variety of molecules and trace elements. With the exception of Oxygen, all other chemicals are provided by the food that we eat. Our digestive system is responsible for converting that food into forms the body can utilize, while ridding the body of metabolic waste products and harmful toxins. The digestive system is based on a series of chemical compounds and enzymes (proteins) that break down the chemical bonds in food so that the more basic building blocks of carbohydrates, fats, amino acids, vitamins and minerals can be absorbed and utilized by our metabolism to provide energy, build new proteins, repair cells etc. Certain vitamins and trace elements present in food cannot be absorbed directly and need to be converted into other forms before they can pass through the intestinal walls. This conversion is most commonly carried out by bacteria in the gut. The various bacterias' own metabolism acts on the vitamins and minerals, appending organic molecules which changes the solubility of the compounds and allows them to pass through the intestine and into the blood stream. These symbiotic bacteria have a further function of protecting the intestine from pathogenic bacteria and yeast When a pathological state exists, this finely balanced symbiosis may be damaged and cease to function normally. Several different states in the gut may exist. Symbiotic bacteria may be damaged, causing the malabsorption of critical vitamins and minerals. If the damage is extensive and/or long lasting, pathogenic yeast and gram negative bacilli will begin to fill the vacuum left by the healthy bacteria. The metabolism of these pathogens is different and foods are no longer broken down in the same way. Proteins that previously would be broken down to their constituent amino acids are only partially digested, leaving long chains of amino acids called peptides. Our entire body is built from proteins, which are themselves built from chains of peptides. Certain peptides are extremely bioactive i.e they interact strongly with other proteins in the body. Another side effects of dysbiosis (incorrect gut microorganisms) is that the gut becomes leaky i.e it passes larger molecules than would normally be the case. Thus peptides, which should normally be broken down to amino acids, leave the gut and enter the blood stream intact, where they are delivered to other organs. Casein and Gluten, a protein and mixture of proteins common in many foods break down to form very potent opio-peptides when acted on by certain pathogenic bacteria. As the name suggests, these peptides have a narcotic action and act on opiate receptors in the brain, triggering major changes in brain function. These are only 2 examples and very little work has been done on identifying the structure and function of peptides created by dysbiosis. The above example is a nice illustration of how the presence of gut dysbiosis can directly effect brain function. Given that depression has its roots in biochemistry, its not too wildly imaginative to suppose that your problems are indeed related to gut dysbiosis. Detoxification is hugely impacted by dysbiosis. Detoxification is, to a large extent carried out by the Liver. Toxic compounds are first oxidized or hydroxylated (Stage I), while Stage II reactions prepare the Stage I metabolites for biliary excretion by covalently conjugating them with highly polar ligands like glucuronic acid or glutathione. These detoxification reactions require vitamin and trace elemental co-factors to provide electrons for chemical bonding. In cases of Dysbiosis, these co-factors may be missing, due to malabsorbtion in the intestine. In addition, the pathogenic bacteria in the gut may metabolize the conjugated toxins, changing their form and allowing them to be reabsorbed into the blood stream. Mercury is usually excreted via the gut in its divalent elemental form. In Dysbiosis it is thought that certain pathogenic bacteria have the ability to methylate the metallic Mercury to its organic form, which would be reabsorbed into the blood stream and carried to target organs like the kidneys and brain.