Harm of addiction. Drugs kill the brain!

Harm addiction to the human brain. What happens to the brain when drugs get into it? What harm do drugs have on their nerve cells? What parts of the brain are made up, what functions do they perform, and how does harm to drug addiction manifest itself in relation to them? What are neurons, and how is information exchanged between them? What drugs "deceive" neurons, and which overload channels of communication between them? How do drugs disrupt the communication system between neurons? What is the limbic system, and which of the "hormones of happiness" does it sing out? What is a down-regulation? How does the addictive effect develop and addiction develops? Drug dependence occurs in the body or in the mind? Are there effective methods of drug treatment? Is it possible to determine that a person is a drug addict?