A new study shows that your decision making skills get severely impaired simply because you haven't slept. Stimulants won't be able to help as well. If you haven't slept, studies show its pretty much the same as making a random choice. Dr Dennis Rosen writes for Psychology Today explains:

Researchers at Harvard Medical School and McLean Hospital recently found that people who were sleep deprived performed less well on a standardized test simulating real-life decision making known as the Iowa Gambling Test than they had at baseline when they were well rested. Even when given stimulants such as caffeine or amphetamines, the ability of the participants to make good decisions only returned to baseline after they had recovery sleep.

[Psychology Today]