How does excess alcohol and drugs consumption affect human beings?

Alcohol consumption — Alcoholic drinks slow down brain activity and weaken its control system when taken in large quantities. It also damages the liver by causing liver cirrhosis.

Drug addiction — Narcotics such as cocaine, heroin, marijuana and opium are harmful substances that can lead to addiction. Once a person starts consuming drugs, a condition of either physical or psychological dependence is produced. During physical dependence, the body requires a continuos supply of drug to be effective. This is called addiction. An overdose of drugs can severely depress the central nervous system with respiratory failure leading to death.