Evidence

What the evidence shows

This section covers what has actually been measured about these drugs, as distinct from what is claimed about them.

Most content about wakefulness and stimulant medication falls into two categories. Clinical sources report whether a drug is approved and broadly effective for its indication. Popular sources report what people say it does. Neither reliably reports the size of the effect, the conditions under which it was measured, or how confident the field is.

That gap is what this section addresses. Where a number exists, it is stated. Where the evidence is thin, that is stated too.

24
randomised trials in the main cognitive review
1990-2014
search window of that review
5
approved drugs for daytime sleepiness
0

direct head to head efficacy trials between them

Weakly supported → firmly established

General intelligence gain
Creativity benefit
Cognition in rested adults
Performance under sleep loss
Sleepiness in narcolepsy
How firmly each claim in this section is supported. Confidence is a judgement about the strength and consistency of the underlying trials, not about the size of the effect.
A note on reading evidence

Two ideas recur throughout this section and are worth stating once.

The idea What it means in practice
Statistical significance is not effect size A finding can be reliably real and also small. A significant improvement means the result is unlikely to be chance. It says nothing about how much performance improved. Popular coverage usually reports only the first number.
Conditions determine results Effects measured in sleep deprived people do not transfer to rested people. Effects measured in patients with a diagnosed disorder do not transfer to healthy volunteers. A result stripped of its conditions is not a result.