I see this cluster occur together frequently. My theory is that consuming gluten generates anti-gluten antibodies that attack the thyroid gland. This occurs because of molecular mimicry–there are components of thyroid tissue that resemble the molecular sequence of gluten. I believe these antibodies initially stimulate the thyroid gland, causing a state of relative hyperthyroidism, which can look like mania, yet these antibodies ultimately destroy the thyroid gland over time, causing a state of relative hypothyroidism, which can look like depression. The path to healing involves eliminating gluten, healing the gut, detox, and cultivating the relaxation response to allow for deep tissue repair.
Have you noticed this cluster in your friends, family or yourself?