There are new concerns for a drug that's been called "Viagra for the brain."

Some people say it’s amazing. Other’s are not sure why more people don't know about it and it is said to help people focus for long periods of time.

Sales of Provigil are booming with a 74 percent increase in the past four years.
 
Currently the drug is only approved for Narcolepsy, Sleep Apnea or for people who work irregular hours.

Some people are now taking it to boost energy and focus. However, doctors warn there have been no studies on the long term effects of Provigil.