A saliva test for teenage boys with mild symptoms of depression could help identify those who will later develop major depression, a new study says. Researchers measured the stress hormone cortisol in teenage boys and found that those with high levels coupled with mild depression symptoms were as much as 14 times more likely to suffer clinical depression later in life than those with low or normal cortisol levels. The test also was tried on teenage girls, but was not as effective. About one in six people suffer from clinical depression at some point in their lives, and there is no biological test to spot depression. "This is the emergence of a new way of looking at mental illness," said study author Joe Herbert of the University of Cambridge.

More kids perking up with coffee

A new study finds that 73 percent of U.S. children and young adults have caffeine in their systems on any given day. Surprisingly, the study in the journal Pediatrics said that among kids, soda consumption is down, but coffee consumption is up. By 2010, just 38 percent of the caffeine ingested by kids came from soda, down from 62 percent in 2000. And while coffee accounted for 10 percent of caffeine intake among youngsters in 2000, it was responsible for nearly a quarter by 2010.

Researchers build new venom library

Venoms from spiders and other animals, fine-tuned by evolution to stun and paralyze prey, are an abundant source of painkillers and other drugs. But screening for useful toxins can be arduous. Venoms contain many active toxins, not all of them suitable for use in humans. And once a potentially effective toxin is identified, researchers must test to determine which neural pathways it might affect. But Yale University researchers have accelerated the process by using DNA cloning technology to build large libraries of spider venoms. Using the process, the scientists have identified a potential new painkiller: a toxin from the venom of the Peruvian green velvet tarantula, below, that blunts activity in an ion channel linked to inflammation and neuropathic pain known as TRPA1.

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