Number of Facebook Friends Could Influence Teens’ Stress Levels, Study Finds

Teens' stress levels could increase with the number of Facebook friends they have, according to a small study published in the journal Psychoneuroendocrinology. The study showed that participants who had more than 300 Facebook friends tended to have higher cortisol levels than those with fewer friends. Meanwhile, more peer interaction on Facebook was linked to lower cortisol levels.

• "Facebook Network and Stress Levels May Be Tied Together" (Doyle, Reuters, 11/30).