Illustration of dopamine. Dopamine is a hormone that acts as an important neurotransmitter in the central nervous system and has an excitatory effect there. fulfills many different tasks in the human body, e.g. for the control of fine motor skills and body movement, but also for the supply of kidneys and digestive tract with blood. Probably best known is its function as a "happiness hormone", i.e. a long-term increase in motivation and drive. Too high or too low a concentration of dopamine is associated with various diseases such as Parkinson's, ADHD and schizophrenia.