On the subject of Drug Scheduling:

Schedule IV

Schedule IV drugs, substances, or chemicals are defined as drugs with a low potential for abuse and low risk of dependence. Some examples of Schedule IV drugs are: Xanax, Soma, Darvon, Darvocet, Valium, Ativan, Talwin, Ambien, Tramadol

So the devil’s lettuce is currently Schedule I with "a high potential for abuse”, but Xanax and Valium are not. Got it. That tells you what you need to know about the DEA’s evaluation processes.