Addiction is a chronic brain disease that presents itself similarly whether you become addicted to a substance (alcohol, prescription drugs and recreational drugs) or a process (such as gambling, sex, eating, and internet use). Addictive behaviours stimulate the brain's reward system similarly to addictive substances, by releasing neurotransmitters such as dopamine.

This stimulation leads people to seek out such pleasurable experiences more and more often. After repeated exposure some people will begin to seek out the experiences compulsively, while at the same time their ability to derive pleasure from the action decreases.