It has been known for a while that high levels of stress can cause a lot of illnesses, mental and physical. One of those ailments is PTSD (post-traumatic stress disorder), which is on the really serious end of the anxiety spectrum. However the exact link between this and stress was not understood. Now a study, published in the latest edition of Molecular Psychiatry, points to the answer. Apparently the culprit that turns stress into PTSD is a hormone called ghrelin. Ghrelin is better known as the chemical that controls appetite and has been (unsuccessfully) tried out in weight control drugs. Apparently during periods of stress the hormone is released and predisposes the brain, through a somewhat circular route, to succumbing to PTSD. Ghrelin levels are elevated by chronic stress. In humans, this might be produced by factors such as, going into war zones, unemployment, bullying, or certain management styles. Interestingly the researchers suggest that this finding may lead to an anti-ghrelin vaccine which could prevent the worst effects of extreme stress. Thisd would be fantastic for workers in high-stress industries (aren’t they all?).