Dopamine is like our brains chemical reward and our brain makes more of it whenever we feel a sense of pleasure or satisfaction. At least that's what we used to think. New research finds that it actually causes us to want and seek out more information until we are satisfied. That's why so many people are addicted to social media sites like Facebook, Twitter, and Instagram. They all have endless feeds of information being fed by humans (& some bots).
It's the opioid system that controls the pleasure and satisfaction the brain feels. The two systems work off of each other, one seeks out information until the other is satisfied, which it never will be because the dopamine system is stronger than the opioid system.