Methamphetamine

Methamphetamine is a powerful lab-made (synthetic) stimulant with high addiction potential.¹ The U.S. Food and Drug Administration (FDA) has approved methamphetamine for treatment of attention deficit hyperactivity disorder (ADHD) as well as for short-term treatment of obesity. It is classified by the U.S. Drug Enforcement Administration (DEA) as a Schedule II stimulant, which makes it legally available only through a nonrefillable prescription. 

However, most methamphetamine used in the United States is illicitly manufactured,² and commonly appears either as a powder or in a crystalline form called crystal methamphetamine (common names include “Tina,” “ice,” and “crystal meth”). 

Methamphetamine is most frequently smoked but can also be snorted, injected, or administered orally³ or rectally.⁴ Methamphetamine use causes increased alertness and talkativeness and decreased appetite, as well as feelings of happiness and well-being, among other immediate effects.¹ However, long-term use may have serious health effects, including unintentional overdose. Methamphetamine is also present in many people who die from overdoses involving fentanyl.

The effects of methamphetamine may be felt immediately or within 20 minutes, depending on how it is used.⁵  When smoked or injected, it enters the bloodstream and brain rapidly and produces an immediate and intense “rush” or euphoria. Other immediate effects include increased wakefulness, confidence, energy, and sex drive, as well as decreased appetite.^{1, 3, 6}

The euphoria wears off quickly, leading to a “crash.” Some people try to avoid this and extend the euphoria by repeatedly taking the drug in a binge pattern. Repeated use in this way increases the risk of developing a methamphetamine use disorder.

Methamphetamine use can have immediate negative health effects, including paranoia, anxiety, rapid heart rate, irregular heartbeat, stroke, increased blood pressure, kidney damage, nonfatal overdose (also called “overamping”), or fatal overdose.^{1, 5, 7, 8, 9}

Methamphetamine affects many of the body’s organs and systems¹⁰ and can cause severe health problems, especially when it is used frequently. These include:

Substance Use Disorder

• Methamphetamine’s unique properties make it extremely addictive.  Repeated use of methamphetamine may lead to methamphetamine use disorder.

Other Mental Health Disorders

• Anxiety, confusion, insomnia, and mood disturbances.¹
• Symptoms of psychosis, such as seeing and/or hearing things that are not there (hallucinations) and deeply believing false stories or ideas (delusions), even when not intoxicated. Heavy drinking and stress have been shown to increase the odds that someone who has experienced methamphetamine-associated psychosis in the past will have psychosis symptoms again.¹²

Effects on Cognition (Thinking)

• Some studies have found decreased cognitive function associated with long-term methamphetamine use, including difficulty with verbal learning and slower reaction times (reduced motor speed).¹³ More research is needed on the impact of methamphetamine use on cognition.¹⁴

Other Long-Term Health Effects

• Increased chances of acquiring bacterial infections, such as a heart infection called infective endocarditis, through shared injection equipment.¹⁵
• Increased chance of acquiring HIV or viral hepatitis through shared injection equipment or sexual behavior associated with methamphetamine use.
• Cardiovascular events like stroke and heart failure.¹
• Tooth decay and loss (“meth mouth”).¹
• Decreased sexual function in men.^{16, 17}

Methamphetamine use can contribute to acquiring viruses such as HIV or hepatitis B and C in two ways:

• Sharing injection equipment, including syringes, may transmit HIV and hepatitis B and C among people who inject methamphetamine.¹⁵
• Because of its effects on sex drive and confidence, methamphetamine use may lead to changes in sexual behaviors, such as more sexual partners and less use of protective measures. This raises the chances of HIV and viral hepatitis transmission.^{18, 19}

Persistent methamphetamine use is the single largest risk factor for acquiring HIV in sexual and gender minorities who have sex with men.²⁰ Among gay and bisexual men, use of methamphetamine in conjunction with sex is sometimes called “partying and playing.”                                                                                                              
Using methamphetamine also makes HIV treatment less effective.²¹

Syringe-services programs, which provide clean injection equipment to people who inject drugs, are highly effective harm-reduction measures, greatly reducing the spread of infectious disease.

Methamphetamine use during pregnancy is associated with adverse health and developmental outcomes, including:

• Increased chance of placental abruption (separation of the placental lining from the uterus) and premature birth.^{22, 23}
• Increased chance of miscarriage and infant death.²²
• Low birth weight, reduced head circumference, and small size of newborn.²³
• Decreased infant alertness, increased stress, and poor quality of movement.²⁴
• Delayed motor development (movement) among toddlers.²⁵
• Altered brain development, possibly resulting in difficulties paying attention in school.²⁶

Research shows that stopping the use of methamphetamine at any point during pregnancy can improve birth outcomes.²⁷

Methamphetamine is a drug with a high potential to become addictive. It can enter the brain quickly and produce an intense “rush” or euphoria that also ends quickly. This makes the drug highly reinforcing and may lead an individual to want to take the drug repeatedly.²⁸ In recent years, nearly two out of three people aged 26 and older who reported past-year methamphetamine use met criteria for a substance use disorder.²

People who have a problem with methamphetamine use have what is called a stimulant use disorder. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)—a reference text professionals use to diagnose substance use and other psychiatric disorders—defines stimulant use disorder as a pattern of stimulant use that leads to clinically significant impairment or distress. This means a person has had two or more of the following symptoms in a 12-month period:²⁹

• Consuming the drug in larger amounts or for longer than intended.
• Persistently and unsuccessfully wanting to cut down or regulate drug use.
• Spending a great deal of time obtaining, using, or recovering from the effects of the drug.
• Experiencing a strong desire to use the drug (craving).
• Failing to fulfill major obligations at work, school, or home because of drug use.
• Continuing drug use even if it causes significant social or interpersonal problems.
• Reducing or stopping other activities because of drug use.
• Repeatedly using the drug in situations where it is unsafe.
• Continuing drug use even when knowing that it causes physical or psychological problems.
• Developing tolerance.
• Experiencing withdrawal symptoms when stopping drug use.

A substance use disorder can be diagnosed as mild when a person has two or three of these symptoms, moderate if they have four or five of these symptoms, or severe with six or more of these symptoms. A severe substance use disorder is what people often call “addiction.”

After a person who uses methamphetamine repeatedly stops taking the drug, they may quickly experience withdrawal symptoms, even if they don’t have stimulant use disorder. These symptoms peak 2-3 days after their last use and may last for a week.³⁰ These symptoms may include:

• Depression
• Anxiety
• Irritability
• Pain and discomfort
• Sleep problems
• Cravings and
• Trouble concentrating

After the acute phase of withdrawal, a person may still experience low mood, anxiety, and cravings for the drug for several months.

There is no FDA-approved medication for methamphetamine use disorder or any other stimulant use disorder. However, there are effective behavioral treatments. The best-studied form of behavioral treatment for methamphetamine use disorder, and the one most associated with treatment success, is contingency management. Contingency management offers people small, tangible incentives such as prizes, cash, vouchers, or gift cards to help keep people from using methamphetamine and to continue treatment.³¹ Other evidence-based behavioral treatment approaches include cognitive behavioral therapy, group support, and motivational interviewing.

NIDA supports research to prevent, treat, and reduce the harms associated with methamphetamine use and use disorder, including studies that:

• Evaluate new medications to help people reduce or discontinue their methamphetamine use, including medications that help reduce the risk of relapse after a period of abstinence.
• Test the safety and efficacy of existing medications to reduce methamphetamine use among people with methamphetamine use disorder alone or with opioid use disorder.
• Evaluate medications to reverse methamphetamine-only overdose.
• Evaluate existing and new behavioral treatments for methamphetamine use disorder.

NIDA also supports research to understand the health impacts of methamphetamine use, including how reducing use affects health and other outcomes. 

Research from the U.S. Centers for Disease Control and Prevention (CDC) shows that methamphetamine is the second most commonly found drug in people who fatally overdose, after synthetic (lab-made) opioids. People overdose on methamphetamine alone or from a combination of methamphetamine and other drugs, particularly the opioids fentanyl and heroin. People may take these drugs together on purpose, or opioids may be added as a hidden ingredient in illicit methamphetamine.³²

Because of this risk, experts recommend giving opioid overdose reversal medications such as nalmefene or naloxone (sometimes sold as Narcan) to anyone experiencing slowed or stopped breathing, which may be signs of an opioid overdose. Research also suggests that drug checking approaches, such as fentanyl test strips, can help people understand what is in their drug supply before use.