The human sleep evidence

What the actual human sleep studies show, and how small they are

This is the unit that decides whether DSIP "works" for sleep, and the honest answer is: we do not really know. The supportive human data is two small studies from the 1980s by Schneider-Helmert. Two independent groups ran similarly designed double-blind trials and did not reach the same conclusion, and several later findings flatly contradict the simple story.

You will appraise each study by modern standards, meet the failed replications and the paradox findings that complicate everything, and learn why "normalisation" became the field’s best guess at what DSIP does.