She was using stimulants but they had worked with less and less effect.

And a small group of students use stimulants themselves as a recreational drug.

Indeed, many students who use stimulants without a prescription report having problems with completing assignments and other tasks that require focus.

People using stimulants may feel happy and excited, and have more energy, concentration or motivation.

Using stimulants to mask daytime sleepiness does not address the actual cause of the problem.

Bannister, who was now a physician, declared that he had never even heard of runners using stimulants.

Then they use artificial stimulants, like caffeine, to mask their sleepiness during the day.

The doctor assists in his escape from police custody; he uses stimulants so Frank can walk.

Many shift workers use stimulants such as caffeine to stay awake at work and/or sleeping pills to aid with sleep during the day.

Using stimulants is a minor offense in the sport, and, at 23, he was young enough to survive his brief ban.