An Overview of Stimulants and How They're Used

Man has put a drip coffee at the counter
Yagi Studio/Digital Vision/Getty Images

Stimulants are a class of psychoactive drug that increases activity in the brain. These drugs can temporarily elevate alertness, mood, and awareness. Some stimulant drugs are legal and widely used. Many stimulants can also be addicting. Stimulants share many commonalities, but each has unique properties and mechanisms of action.

Drugs that are classed as stimulants include:

  • Caffeine
  • Nicotine
  • Cocaine
  • Methamphetamine
  • Prescription stimulants


Caffeine is the most widely used psychoactive drug in the world, found in coffee, tea, cocoa, chocolate candy, and soft drinks. While caffeine has several positive effects such as increasing energy and mental alertness, heavy use can cause symptoms such as anxiety and insomnia. Caffeine is physically addictive, and withdrawal symptoms can include headaches, fatigue, and irritability.


Nicotine is considered one of the three most widely used psychoactive drugs in the world despite the fact that there are few (if any) medical uses for the drug. During the early to mid-twentieth century, smoking was considered fashionable. Reports of the adverse health consequences have led to cigarette use being increasingly shunned. However, the Centers for Disease Control and Prevention (CDC) reports that in 2014, approximately 17 percent of U.S. adults over the age of 18 (around 40 million individuals) smoke cigarettes.

The National Institute on Drug Abuse reports that tobacco use is a leading preventable cause of death, disease, and disability in the U.S., with cigarette use attributed to more than 480,000 premature deaths each year.


Cocaine is an illegal psychoactive drug made from the leaves of the coca tree. During the late 1800s, psychoanalyst Sigmund Freud advocated the use of cocaine as a therapeutic treatment for psychological disorders, but later realized the addictive properties of the drug. During the early 1900s, cocaine was legal in the U.S. and could be found in many over-the-counter medications.

In 1906, the government began requiring manufacturers to label cocaine-containing products and began placing serious restrictions on distribution by the early 1920s. Cocaine is a restricted substance and its use and sale are considered illegal in most cases. Today, cocaine is one of the most frequently used illegal drugs in the United States.

Cocaine is rapidly absorbed from any administration point, including being snorted, inhaled, injected or taken orally. The drug reaches the brain quickly and is then distributed to other tissues throughout the body. Cocaine is rapidly metabolized by enzymes in the liver and plasma in approximately 30 to 60 minutes but can be detected in urine tests for up to 12 hours after administration.


Methamphetamine, also known as meth, is extremely addictive and destroys tissues in the brain, which can lead to brain damage.

Prescription Stimulants

Prescription stimulants are a group of psychoactive drugs that affect the central nervous system and the autonomic nervous system. Some of the effects of using these drugs include tremors, vasoconstriction, restlessness, tachycardia, insomnia, agitation and loss of appetite.

These agents were once widely used in obesity and weight loss treatments, but their addictive properties have caused them to be rarely used today for that purpose. 

Prescription stimulants are currently used to treat some physical and psychological disorders, including attention-deficit hyperactivity disorder (ADHD) and narcolepsy. Common names of prescription stimulants include Ritalin, Adderall, and Dexedrine. Prescription stimulants work by enhancing the effects of dopamine and norepinephrine and can lead to increased blood pressure, respiratory function and euphoria.

Was this page helpful?

Article Sources

  1. Daly JW, Holmén J, Fredholm BB. [Is caffeine addictive? The most widely used psychoactive substance in the world affects same parts of the brain as cocaine]. Lakartidningen. 1998;95(51-52):5878-83. PMID: 9889511

  2. Juliano L. M., & Griffiths, R. R. (2004). A critical review of caffeine withdrawal: Empirical validation of symptoms and signs, incidence, severity and associated features. Psychopharmacology, 176, 1-29. DOI:


  3. Crocq MA. Alcohol, nicotine, caffeine, and mental disorders. Dialogues Clin Neurosci. 2003;5(2):175-85. PMID: 22033899

  4. US Department of Health and Human Services. The health consequences of smoking—50 years of progress: a report of the Surgeon General. Atlanta, GA: US Department of Health and Human Services, CDC, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014.

  5. National Institute on Drug Abuse, "Tobacco/Nicotine and E-Cigs"

  6. National Institute on Drug Abuse, "DrugFacts: Cocaine"

  7. Chen X, Zheng X, Zhan M, Zhou Z, Zhan CG, Zheng F. Metabolic Enzymes of Cocaine Metabolite Benzoylecgonine. ACS Chem Biol. 2016;11(8):2186-94. PMID: 27224254

  8. Thompson, P. M., Hayashi, K. M. Simon, S. L. London, E. D., & others. (2004). Structural abnormalities in the brains of human subjects who use methamphetamine. Journal of Neuroscience, 24, 6028-6036. DOI: