Oxytocin is known as the hormone that promotes feelings of love, bonding and well-being. It's even being tested as an anti-anxiety drug. But new research shows oxytocin also can cause emotional pain. Oxytocin appears to be the reason stressful social situations, perhaps being bullied at school or tormented by a boss, reverberate long past the event and can trigger fear and anxiety in the future. That's because the hormone actually strengthens social memory in the brain.