Posted 11/13/2018 3:45 PM (GMT -7)
Making it through all of the stages of sleep (1-4 + REM) are critical. Each stage serves a particular purpose we're not 100% sure about, but we know they're all important. As an example, they've done studies where depriving REM sleep alone has significant effects on the processing of painful stimuli.
Disrupted sleep can contribute to many other health issues such as hypertension, certain metabolic diseases, and other pathologies. A paper titled "Medications for the Treatment of Sleep Disorders: An Overview" from Fagel et al in 2001 lists benzodiazepines (which includes Xanax, Ativan, and others) as REM "suppressors". To quote the paper directly, "Benzodiazepines are rapid eye movement (REM) sleep–suppressant medications, and withdrawal often results in episodes of increased REM sleep (REM sleep rebound). REM sleep is known to have a role in learning and memory consolidation." However, common consensus in research is that short-term usage of benzos as sleep aids can be better for some people than a hard-core sleep aid like Ambien.
If you're curious, the paper can be found here. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC181172/