With finals approaching, students are breaking out the study pills — and they aren't the only ones.

Both legal and illegal uses of prescription stimulants like Adderall, Ritalin, Concerta, and Vyvanse continue to rise for everyone from young children to adults in the workplace.

For people with ADHD, these drugs can be lifesavers.

But before jumping on the bandwagon, here are some facts about Adderall and other stimulants you should know.

1. Between 2007 and 2012, the number of adults with ADHD prescriptions tripled.

In 2007, there were 5.6 million monthly ADHD prescriptions for people aged 20 to 39. By 2012, that number had nearly tripled, getting close to 16 million.

The number of adults who have an ADHD prescription is now rising much faster than the number of children getting the same drugs. In the case of adults, a lot of that rapid growth is driven by women who are getting a prescription for adult ADHD.

2. Stimulant-related emergency-room visits have tripled in recent years.

Though some don't see them as drugs, stimulants — methylphenidate or amphetamines like speed — carry real risks. Emergency-room visits for people 18 to 34 due to nonmedical stimulant use tripled from 2005 to 2011, though those numbers also include things like caffeine pills.

3. Every major ADHD drug has been cited by the FDA for false and misleading advertising.

According to The New York Times, the FDA has "cited every major A.D.H.D. drug — stimulants like Adderall, Concerta, Focalin and Vyvanse, and nonstimulants like Intuniv and Strattera — for false and misleading advertising since 2000, some multiple times."

That story quotes experts who argue that marketing — and, in some cases, false marketing — by pharmaceutical companies is behind much of the rise in the number of people taking Adderall, Vyvanse, Concerta, and Focalin.

They note that sales of stimulants have quintupled since 2002, and point to potentially misleading quizzes that let adults test whether they have ADHD. The Times polled more than 1,100 adults and found that more than half scored in a range that said they "possibly" or "likely" suffer from ADHD.

4. If you are creative, Adderall could impair your abilities.

Researchers recently had a small group of young adults perform a series of tasks related to creativity to see what impact Adderall might have.

Adderall didn't affect performance on all tasks, but on the tests where it did have an effect it seemed to help those who were low-performing. However, people who had performed well on the test without taking stimulants showed either no change or did worse while taking Adderall.

5. The typical college student who uses Adderall without a prescription is white, male, and in a fraternity.

Numerous studies have shown that as many as 55% of students who are in fraternities misuse stimulants.

White male drinkers at competitive schools are also more likely to use stimulants, especially if their GPA is below average.

6. If you like the feeling of Adderall or Ritalin, you may be less likely to develop ADHD.

A recent study had the surprising finding that people who were genetically predisposed to feel euphoria when on stimulants were also less likely to have genes that predisposed them to ADHD and schizophrenia. This might explain why some people who don't have ADHD may be especially likely to abuse stimulants — it makes them feel particularly good.

7. The placebo effect may account for some of the perceived cognitive benefits of Ritalin.

Some research shows that people who think they are going to be given a drug like Ritalin or Concerta don't show cognitive improvement but do pay better attention and act more engaged.

In a recent study, college students were given either a placebo pill that they thought was Ritalin or no pill before taking a series of cognitive tests. When they thought they had taken Ritalin, students said they were more alert and able to focus on the work.

8. Many people who use Adderall without a prescription don't think they are taking a drug.

One survey of undergraduates found that only 2% thought using Adderall was "very dangerous." Students told researchers that Adderall was "not a drug" but instead "a study tool." Others compared it to drugs like cocaine and said Adderall was "kinda the opposite" since they used to be better at school and it was perfectly safe since doctors prescribe it.

9. Up to a third of college students use stimulants — and they don't think it's cheating.

While it's hard to estimate illegal or off-label usage of prescription stimulants, one recent study showed that almost 20% of Ivy League students used an unprescribed study aid at least once while in college. Overall, estimates of the percentage of college students that have illegally taken stimulants range from 6.9% to 35.6%.

Of the Ivy League students surveyed, 33% did not view using stimulants as cheating, though 41% did. The remaining 25% were unsure.

10. People's unrestrained tweeting about Adderall gives us a fascinating window into how it is used.

People aren't scared to mention on Twitter that they are using Adderall, and though there are questions about how reliable behavioral information gathered from Twitter is, data scientists are taking note.

Computer-science researchers at Brigham Young University analyzed tweets that mentioned "Adderall" between November 2011 and May 2012. There were an average of 930 Adderall-related tweets a day, but that number rose to 2,813 on Dec. 13 and 2,207 on April 30 — a spike the researchers attributed to finals cramming.

And geotagging revealed where people were tweeting about Adderall most: The largest clusters of tweets about Adderall per 100,000 students were near universities in the Northeast and South, a finding that matches previous research on where students are most likely to use "study aids."

11. Pro baseball players take ADHD meds at rates that are much higher than normal.

Baseball players have historically used stimulants as performance-enhancing drugs.

After Major League Baseball announced a stimulant ban, at about the same time regulators were cracking down on steroid abuse, the number of pro baseball players who requested therapeutic exemptions that would allow them to continue to take stimulants jumped from 28 players to 103, or 8% of the league. The number is now even higher: In 2013, 119 requested those exemptions.

Those rates are more than double the 4% of adults that the National Institute of Mental Health says are affected by ADHD. Some say that professional athletes are more likely to have ADHD than the rest of the population, but not everyone agrees.

"This is incredible. This is quite spectacular," said Dr. Gary Wadler of the World Anti-Doping Agency, when the MLB ban led to a jump in therapeutic exemptions. "There seems to be an epidemic of ADD in major league baseball."

12. Mixing stimulants with alcohol may increase the risks.

Lots of college kids and young adults take stimulants like Adderall when they go out, either to stay up or just for the euphoric effect. But drinking may increase the risk of heart problems for people taking stimulants, even when they don't take an excessive amount of medication. In at least one case, researchers documented a heart attack in an otherwise healthy 20-year-old who took 30 mg of Adderall after drinking.

13. Almost 20% of high-school boys have been diagnosed with ADHD, and more kids are prescribed stimulants than ever before.

Last year, a CDC report showed that the number of kids age 4 to 17 who received a diagnosis of ADHD rose 41% over the last decade. About two-thirds of kids with a diagnosis are prescribed stimulants like Adderall and Ritalin.

Boys receive ADHD diagnoses at more than twice the rate of girls, and are also more likely to receive prescription stimulants. Almost 20% of high-school boys have received an ADHD diagnosis.

Some people argue that this reflects better recognition and diagnosis of ADHD, but others say that it's a dangerous overuse of medicine to calm kids down and help them out in school. A recent Esquire article argued that the high rate of ADHD diagnoses among boys in particular is due to both a misunderstanding of boys' behavior and increased marketing efforts by pharmaceutical companies.

Quinn Dombrowski/flickr

14. ADHD drugs can be addictive.

Drugs like Adderall and Ritalin release a rush of dopamine in the brain, giving many people a sense of euphoria. They help people feel alert, awake, and focused, but make it hard to sleep — making it more tempting to take another pill when you're exhausted the next day. People also develop a tolerance to these drugs, requiring more and more over time to achieve the same effect. Stimulants are considered addictive because it can be easy to become dependent on them.

15. Doctors have ignored FDA warnings about prescription stimulants.

FDA warnings that Adderall, Ritalin, and other prescription stimulants are addictive and can have potentially dangerous side effects also haven't deterred doctors from prescribing them. Four years after a 2004 FDA advisory about possible cardiac risks, doctors hadn't significantly changed the way they prescribed stimulants.

16. Stimulants don't necessarily provide cognitive enhancement in kids.

Although stimulants help people focus and pay attention, they don't necessarily improve academic performance in students with ADHD. They may help people sit still longer and lessen disruptive behavior in class, but not many direct cognitive improvements have been shown.

17. Stimulants might provide some cognitive enhancement in people with adult ADHD.

Among adults, a study showed that ADHD subjects who regularly took medication performed better on an IQ test than ADHD adults who were unmedicated. Researchers say that their higher scores could mean that their medication helped them do better on the test, or it could mean that the adults who would have done better on the test anyway were the same ones that would have sought out treatment.

18. Stimulants can improve memorization skills ...

One of the main reasons people take stimulants without a prescription is to do better at school or work. Although the cognitive benefits of Adderall and Ritalin are far from clear, one thing they do seem to help with is rote learning. A few studies have shown that people who memorize things while on stimulants may be better at remembering those words or terms when tested later on.

19. ... But probably don't do much for working memory.

A review of different studies on the cognitive benefits or harms of stimulants found limited effects on working memory, the ability to hold and manipulate different pieces of information simultaneously.

In most tests of working memory, stimulants didn't do much to help or hinder people, including sleep-deprived young adults. Some people who performed poorly on tests to begin with did show some improved performance, leading researchers to think that stimulants may be better at correcting deficits than at enhancing performance.

20. Scary side effects include heart attacks and sudden death.

The scariest of the listed side effects for Adderall is the risk of sudden death, along with a series of other heart problems that stimulants can cause. Most of the sudden-death cases have occurred with people who had structural issues with their heart or other health complications, and at least one fatality involved a toxic level of medication. Another case was associated with vigorous exercise. Other cardiac side effects include high blood pressure and tachycardia, or a sped-up heart rate.

21. In rare cases, stimulant abuse has led to mental illness and psychosis.

In the FDA's medication guide to Adderall, they warn people to call doctors immediately if they experience mental problems, "especially seeing or hearing things that are not real, believing things that are not real, or are suspicious." Worsened mental illness for adults and psychotic symptoms for children are among the listed side effects.

The medical literature includes case reports of methylphenidate, the active ingredient in Ritalin and Concerta, triggering depression in a 7-year-old and terrifying hallucinations in a 15-year-old. And The New York Times reported on the highly unusual but tragic case of Richard Fee, a 24-year-old from Virginia Beach. Fee developed very serious mental-health problems while battling a severe addiction to prescription stimulants and ultimately took his own life.