How Low Levels of Dopamine, Endorphins, Serotonin, and Oxytocin Can Affect Your Mood Happiness is a complex emotion that is influenced by a variety of factors, including our thoughts, behaviors, and brain chemistry. When we are happy, our brains release chemicals such as dopamine, endorphins, serotonin, and oxytocin. These chemicals have a number of positive effects on our … [Read more...] about How a Lack of Happiness Affects You: The 4 Brain Chemicals and Their Symptoms