Peter Tripp's 1959 wakeathon (201 hours without sleep, broadcast live on New York radio) and Randy Gardner's 1964 record attempt (264 hours — 11 days) are two of the most documented cases of extreme sleep deprivation in history.

What Happened to Peter Tripp

By day 3: visual hallucinations. By day 5: paranoid delusions — he believed a doctor trying to examine him was an undertaker coming to bury him alive. By the end: complete loss of identity, screaming in panic. Recovery took months.

Randy Gardner — A Different Picture

Gardner, 17, experienced cognitive degradation, irritability, and memory problems — but far less severe psychological breakdown than Tripp. Researchers attributed the difference partly to age and partly to Tripp's stimulant use during the attempt.

The Research Consensus on Sleep Deprivation

• After 24 hours: cognitive impairment equivalent to a blood alcohol level of 0.10%
• After 17 hours: equivalent to 0.05% BAC
• Memory consolidation, emotional regulation, immune function, and metabolic processes all degrade measurably
• Chronic mild sleep restriction (6 hours/night) impairs performance as severely as total deprivation — but subjects adapt subjectively and stop noticing their own impairment

Reference:

Wikipedia: Sleep Deprivation

https://en.wikipedia.org/wiki/Sleep_deprivation