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Learn about stimulants and their impact on the brain.

Stimulants are legal and illegal substances that can make people feel more active, alert, energetic, and focused in the short term. Stimulants speed up the central nervous system — as opposed to depressants, such as alcohol and benzodiazepines, which have the opposite effect.

Like many other drugs, stimulants can be misused, cause serious health problems, and lead to dependence and withdrawal. If you find it hard to stop using stimulants, a doctor may diagnose you with stimulant use disorder.

Recovery from stimulant misuse or dependence is possible.

Common stimulant drugs

Stimulants come in over-the-counter, legally prescribed, and illicitly obtained forms.

Over-the-counter stimulants

These are common examples of stimulants people can buy at a store:

Caffeine. Caffeine is in coffee, tea, energy drinks, sodas, and supplements, and is generally safe at low doses (about 400 milligrams or less). However, pregnant people are often advised to limit caffeine consumption and kids under 12 are told to avoid it.

Nicotine. Nicotine is in tobacco products like cigarettes and nontobacco products such as vapes. In the United States, people must be at least 21 years old to legally purchase any tobacco products. Nicotine is an addictive substance that can lead to long-term dependency on tobacco products that contain highly toxic carcinogens.

Ready to quit smoking or vaping nicotine? Help is available.

If you smoke and you want to quit, know that you don’t have to go "cold turkey." Over-the-counter nicotine replacement therapies and prescription medications have been shown to help people quit, and additional counseling can help ensure your success in quitting smoking. Learn more.

Prescription stimulants

Food and Drug Administration (FDA)-approved prescription stimulants can benefit people diagnosed with certain medical conditions, including ADHD and narcolepsy. Common FDA-approved stimulants include the following:

Dextroamphetamine (known by the brand name Dexedrine). Health care providers prescribe this medication primarily to control the symptoms of attention-deficit/hyperactivity disorder (ADHD) and sleep disorders such as narcolepsy. It is taken by mouth in a tablet, liquid, or extended-release capsule.

Dextroamphetamine-amphetamine (known as Adderall). This medication is also prescribed to treat ADHD and narcolepsy in adults and children. It comes in immediate-release and extended-release tablets.

Methylphenidate (known as Ritalin or Concerta). This is another drug approved to treat ADHD in adults and children. It can also be used to treat narcolepsy in adults. Methylphenidate is prescribed as an immediate- or extended-release tablet or as a transdermal patch.

Modafinil (known as Provigil). This prescription stimulant is approved for treating mild to moderate narcolepsy as well as shift work sleep disorder. It is also prescribed off-label to treat depression and other conditions.

Most prescription stimulants have the potential to be misused and cause harm. Amphetamine-based prescription stimulants — such as Dexedrine and Adderall — have a higher risk for causing misuse and dependence than methylphenidate-based stimulants like Ritalin and Concerta do.

Are you at risk of misusing a prescription stimulant?

An average of 16 million adults in the U.S. use prescription stimulants in a given year. About 5 million of these individuals misuse the substances, and 400,000 have a stimulant use disorder. You may be more likely to develop a problem with stimulants if you do not take a prescribed dose as directed or if you take prescription stimulants even though you don’t need them. And you may be more likely to develop a dependence on these drugs if you have misused these or other substances in the past. Learn more about the risk factors for misuse of prescription stimulants.

Illicit stimulants

These are common stimulants that are most often obtained illegally for recreational use:

Cocaine. Cocaine is a highly addictive substance. It comes in a powder that is snorted through the nose, rubbed on gums, or dissolved into a liquid and injected. Crack cocaine is made into a rock that is heated and smoked or can be dusted onto marijuana or tobacco and smoked. Depending on the amount and form, cocaine produces a short-term “high” with effects ranging from happiness to violence. These effects wear off quickly, leading some to take more cocaine to maintain the feelings. This can lead to physical and mental health problems, dependence, and even overdose. Cocaine laced with fentanyl is even more addictive and often deadly.

MDMA (also known as ecstasy or molly). This is a pill, powder, or liquid that is chemically similar to both stimulants and hallucinogens. It can make people feel euphoria, emotional warmth, and sexual closeness, and it also distorts senses and perceptions. People who take the drug generally feel the effects for three to six hours. MDMA is not considered as addictive as cocaine. However, at high doses, it can harm the body’s ability to regulate temperature, causing organ failure and death.

Methamphetamine. Methamphetamine, or meth for short, is a highly potent, addictive, and dangerous stimulant. Coming in glass crystals or rocks, meth is smoked, swallowed, snorted, or dissolved and injected. The high from meth comes on rapidly but is short-lived, causing people to seek more of the drug and become dependent. People may stay on meth for hours or days at a time, losing sleep and nourishment. Use of meth can cause lasting physical and mental scars.

Are you in danger of taking a fentanyl-laced stimulant?

Illicit stimulant drugs such as cocaine and methamphetamine are often found laced with illegally manufactured fentanyl. Fentanyl-laced drugs carry an even greater risk of overdose and death. Test strips may detect the presence of fentanyl in drugs, but they are not 100% reliable.

If you suspect someone is experiencing a fentanyl overdose, call 911 and administer naloxone. Keep the person awake and lying on their side until first responders arrive. Learn more about naloxone.

Side effects of stimulants

Misuse of or dependence on stimulants can cause a range of harms:

  • Caffeine use over a prolonged period can cause physical and mental symptoms, including restlessness, jitters, insomnia, elevated heart rate, dehydration, and anxiety. People who consume a lot of caffeine may experience withdrawal symptoms when they stop using it.
  • Nicotine is an addictive substance, and smoking nicotine products can lead to dependence. And while the nicotine itself does not cause cancer, nicotine products like cigarettes contain other chemicals that can lead to serious health issues, including cancer.
  • Pharmaceutical stimulants not used as intended or prescribed can cause anger, paranoia, and psychosis and lead to dependence (i.e., stimulant use disorder). If not dosed properly or not taken as prescribed, prescription stimulants can also cause irregular heart rhythms and other adverse or even life-threatening effects.
  • Illegal stimulants — whether in their pure form, laced with fentanyl, or combined with other drugs — can cause serious physical and mental health issues including dependence, overdose, and death.

Impact on the brain. Short-term use of stimulants interferes with or changes brain neurons and circuits. These drugs can affect brain processes related to memory, learning, and other cognitive functions. Stimulants can also cause dependence by acting on the brain’s reward system, causing people to crave them. Long-term exposure to cocaine and methamphetamine in particular may lead to cognitive impairment that persists for several months or more after use is stopped.

Find treatment for stimulant misuse


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Content reviewed by Dr. Jasleen Salwan, MD, MPH, FASAM, February 2023.