The Most Addictive Substances in the World

Posted: Jan, 12th 2019

Drug addiction is a disease that impacts the brain circuitry and can alter and impair behavior; it is classified by an inability to control drug use. Drugs that are addictive directly impact the pleasure center of the brain and repeated use changes the way a person processes information. Addictive qualities of drugs can be enhanced by how good the person feels when using them and how bad the user feels when they wear off. Researchers considered several factors when determining the most addictive substances:

  • How much physical harm the drug causes
  • How much cognitive harm the drug causes
  • The extent to which the drug activates the brain’s dopamine system
  • How pleasurable the drug is reported to be
  • How easily the person will become reliant on the drug
  • The street value of the drug



Heroin is considered the most addictive drug. It is an opiate drug made from morphine. It enters the brain rapidly and binds to opioid receptors on cells in many areas, especially those involved in feelings of pain and pleasure. It can also affect receptors controlling heart rate, sleeping, and breathing. Heroin causes the level of dopamine in the brain’s reward system to increase by up to 200% in experimental animals. Heroin is considered so dangerous because the dose that can cause death is only five times greater than the dose required for a high.



Cocaine increases levels of the natural chemical messenger dopamine in brain circuits related to the control of movement and reward. Cocaine increases euphoria, excitement, and alertness, and according to the Drug Enforcement Administration (DEA), it is highly addictive. In experiments on animals, cocaine caused dopamine levels to rise more than three times the normal level Depression and cravings are some of the more prominent features of cocaine withdrawal that make the drug more addictive and harder to stop using.



Experts have identified nicotine as the third most addictive substance. Nicotine is the main addictive in ingredient of tobacco. When somebody smokes a cigarette, nicotine is rapidly absorbed by the lungs and delivered to the brain. Nicotine takes effect within 10 seconds of being smoked and wears off in a matter of hours, meaning that individuals may wish to have another cigarette shortly after the last one, NIDA reports. Laboratory animals have the good sense not to smoke. However, rats will press a button to receive nicotine directly into their bloodstream which causes dopamine levels in the brain’s reward system to rise by about 25%-40%.



The fourth most addictive substance is barbiturates which are part of a class of drugs that were initially used to treat anxiety and to induce sleep. They interfere with chemical signaling in the brain; the drug works by shutting down various brain regions. At low doses, barbiturates cause euphoria, but at higher doses they can be lethal because they suppress breathing.



Alcohol is the most regularly used addictive substance in America. Experts report 1 out of every 12 adults suffering from an alcohol abuse or dependency issue, the National Council on Alcoholism and Drug Dependence (NCADD) reports. Alcohol effects dopamine levels to enhance mood but it also serves as a central nervous system depressant, slowing down nerve firings and the functions of the central nervous system. This results in lowered blood pressure and heart rate. It also promotes sedation and impairs motor skills and cognition. Alcohol has many effects on the brain, but in laboratory experiments on animals it increased dopamine levels in the brain's reward system by 40% to 360% -- and the more the animals drank the more dopamine levels increased.