Cocaine comes from the leaves of the coca plant and is usually refined into a white powder form. People often snort, smoke, or inject it to feel its effects quickly. When a person uses cocaine, it causes a rush of dopamine in their brain, which leads to the feelings of pleasure and energy. However, these effects don't last long, and the person may feel the need to use more cocaine to keep feeling good. This is the beginning of the process that can lead to addiction.