Amphetamines are illegal drugs. They can be both lawful and illegal. They are lawful when prescribed by a doctor and used to treat medical conditions such as obesity, narcolepsy, or attention deficit hyperactivity disorder (ADHD). Amphetamine use can lead to addiction.
Amphetamines are unlawful when used to get high or increase performance without a prescription. They are known as street or recreational drugs in this situation, and their use can lead to addiction. This section of the article discusses this characteristic of amphetamines.

There are different kinds of street amphetamines. Common ones and some of their slang terms are:
Amphetamine: goey, louee, speed, uppers, whiz
Dextroamphetamine (ADHD medicine used illegally): dexies, kiddie-speed, pep pills, uppers; black beauty (when combined with amphetamine)
Methamphetamine (crystal solid form): base, crystal, d-meth, fast, glass, ice, meth, speed, whiz, pure, wax
Methamphetamine (liquid form): leopard’s blood, liquid red, ox blood, red speed
Illegal amphetamines come in different forms:
Pills and capsules
Powder and paste
Crystal
Liquid
They can be used in different ways:
Swallowed
Dabbed onto the gums
Inhaled through the nose (snorted)
Injected into a vein (shooting up)
Smoked .

Amphetamine is a stimulant of the central nervous system. Its use causes an increase in specific types of brain activity, resulting in feelings of increased energy, attention, and confidence, as well as the ability to produce pleasant euphoria in a dose-dependent way. According to the Center for Substance Abuse Research, amphetamine was initially manufactured in Germany in the late 1800s; however, its stimulant qualities were not fully appreciated until the 1930s, when it was used to treat nasal congestion.
Amphetamines are psychostimulant medicines, which means they accelerate the transmission of messages between the brain and the body.
Doctors use certain forms of amphetamines to treat illnesses such as attention deficit hyperactivity disorder (ADHD) and narcolepsy (where a person has an uncontrollable urge to sleep). Parkinson’s disease has also been treated using amphetamines. Other amphetamines, such as speed, are manufactured and marketed illegally. Amphetamines have also been used as a performance enhancer. Crystal methamphetamine is the most potent type (ice).

Fast facts about amphetamines
Amphetamines are central nervous system (CNS) stimulants.
They are used to treat ADHD and narcolepsy.
Adverse effects include restlessness, acne, and blurred vision.
Rarer side effects include seizures, heart problems, and psychosis.
Amphetamines are used for recreational purposes. They are addictive.