The Thinking Meat Project

Leptin and depression

Leptin, which has been recognized for awhile as a key hormone in controlling appetite and weight, is also linked to depression, at least in rats. It makes sense that appetite is linked to mood; who hasn’t felt too anxious or depressed to eat? But it’s not clear how this recent work with rats might translate to humans. (Leptin was supposed to be a big anti-obesity drug because of how it acted in rats, but it didn’t work the same for people.) In a recent study, stressed rats had lower levels of leptin in their blood and also showed signs of depression, which were reversed when the rats were given leptin injections. If leptin does turn out to be useful in treating human depression, scientists would likely need to develop a way to reproduce the effect with another molecule that has only the anti-depressant effects, to avoid side-effects due to all the other roles that leptin plays in the body. I suspect we’re in such early days in figuring out how this all works that people are going to look back 100 years from now and be amused at our misconceptions based on the bits and pieces we know so far, but we’ve got to keep gathering the bits and pieces to try to assemble them into a coherent picture. (There’s a technical term, by the way, for the particular type of stress the rats were subjected to: chronic unpredictable stress, or CUS. I’ll have to try that one out in conversation the next time I’m complaining about my job.)

http://www.nature.com/news/2006/060116/full/060116-3.html

http://www.medpagetoday.com/Psychiatry/Depression/tb/2496