I've read it in several versions, never with any attribution. It seems to clearly be creepypasta (that is, a creepy copy-pasted story that circulates). A particularly powerful example of it, too.

I think the real questions for the historians here are "how, if at all, did the Soviets experiment on sleep deprivation?" and perhaps "what particularly haunting experiments did the Soviets conduct on live humans?"

The Russian Sleep Experiment is fiction, written by an anonymous writer of the Internet. If you are interested in possible real life cases, follow /u/krazehades advice!

Are you talking about this story? If so I think it's completely fabricated.

I know that sleep deprivation has been used as a torture device in Guantanamo.

There is also a very rare, horrific disease called Fatal familial insomnia Where you get increasingly worse insomnia until you eventually die.

These examples aren't medical in nature, but they might be a good starting point for learning about sleep deprivation.