What you post on Instagram... and how you post it... may offer valuable clues to the state of your mental health--
An algorithm created at Harvard and the University of Vermont scans Instagram and correctly identified depression 70 percent of the time. That's compared with just 42 percent for doctors. (To be fair, those were general practioners, not psychologists)
Researchers found that depressed people were more likely to post photos with "bluer, grayer, and darker" colors. People who weren't depressed tended to use filters that brightened up an image.
Another sign? Fewer faces in your photos.