Amphetamines are very addictive stimulants. They speed up functions in the brain and body. They come in pills or tablets. Prescription diet pills also fall into this category of drugs.

No matter how a person takes amphetamines, these drugs hit with a fast high, making the user feel powerful, alert, and energized.

These "uppers" pump up heart rate, breathing, and blood pressure, and can also cause sweating, shaking, headaches, sleeplessness, and blurred vision.

Long or lasting use may cause hallucinations and intense paranoia.

Even after users stop taking amphetamines, they may still have problems such as aggression, anxiety, and strong cravings for the drugs.