All of these can be genetically predetermined and some can be caused by a head injury or antibiotic use or virus etc etc- Inadequate Copper Utilization or Insufficiency Pyroluria Diabetes Insipidus or Insufficient or Resistant ADH secretion (me) Overgrowth of Lactic Acid Producing Bacteria Prostaglandin E2 excess, E1 Deficiency (treat with evening primrose and omega fish oil or eat oily fish) (take with fat) Sex Hormone Deficiency Elevated Sex Hormone Binding Globulin (Leading to Decreased Free Circulating Sex Hormones) Dopamine Resistance (treat with amphetamine like stimulants) Insulin Resistance (could be secondary to gut inflammation) Overgrowth of Bacteria Producing Enzymes that Destroy Vitamin B1 and B3 Celiac Disease Other Food Allergies Brain Malfunction (NDMA/AMPA Receptor Dysregulation Leading to Neurotransmitter Malfunctioning) DHEA and or Cortisol Insufficiency Aldosterone Insufficiency Hypothyroidism Inability to Convert T4 to T3 in adequate amounts/thyroid hormone resistance (selenium deficiency possible) Gaba Deficiency (found in one study to have high excretion rate in CFS patients) Beta Alanine Deficiency (found in one study to have high excretion rate in CFS patients) Gallstones Leading to Digestive Enzyme Deficiency (blocking the bile duct and enzyme secretion from pancreas and gallbladder) Overgrowth of Iron Absorbing Bacteria Downregulation/Deficiency of Beta Adrenergic Receptors (Possibly from former or current Hypothyroidism) Inadequate Intake of Dietary Fat (Leading to cholesterol and hormone deficiency) Biotin Deficiency (causing malfunction of enzymes like Lactate Dehydrogenase and Partially Inhibiting the Krebs Cycle) HGH deficiency Opiate Deficiency/Beta Endorphin Deficiency (Shown in Studies to be Deficient in CFS patients) Genetic Deficiency of Any Neurotransmitter Elevated Angiotensin Converting Enzyme (Leading to Decreased Dopamine Levels) This was found to be elevated in majority of CFS patients. Oxytocin Deficiency By no means covers all of it. I'm sure West Nile Virus or Malaria could be thrown in there...but a lot of these are overlooked. The abnormal vasopressin secretion is an interest of mine because that's exactly what I have. I have diabetes insipidus as diagnosed by electrolyte concentration comparison of urine and plasma (and of course peeing and drinking all day without replacement therapy)..yet my ADH level supposedly was high on one test. That test could have been bad. Who knows. Add your own list these are just some of my observations. For me going without vasopressin is even worse than going without cortisol.