Addiction is a disease in which the individual engages in the use of a substance or a behavior, despite harmful consequences.  Addiction could include the use of substances, such as alcohol, inhalants, opioids, cocaine, nicotine, and others, or behaviors such as exercise, eating, gambling, and sex.  Scientific evidence reveals that addictive substances and behaviors play a part in primary neurobiological features that intensely activate brain pathways to experience reward and reinforcement, often involving the neurotransmitter dopamine.