When dopamine levels are elevated this reward pathways reinforces the use of the drug?

Dopamine is neurotransmitter produced naturally by the brain's pleasure and reward center (limbic system). Dopamine is produced natural when u are eating ice cream, exercising or watching your favorite movie. What illegal drugs or antidepressants do is that they cause an abnormal production of dopamine in the brain which causes the natural dopamine producing site to eventually stop dopamine production. The drug user will now be subservient on the drug to him or her happy(addiction).