The Buddha's Noble Truths About Stress

The Buddha says no matter how you live your life, you're going to experience old age sickness, loss and separation from the loved. It's the nature of mind to seek a sense of safety and status as defenses against life's unreliability - even if these states are very, very short lived. Dopamine essentially stops secreting because it would didn't, there would be nothing motivating us to hunt again for more things that originally helped us survive.