A psychiatrist who operated a clinic in West Hollywood, and his office manager, were arrested on Tuesday on federal charges of conspiring to distribute controlled substances.

Federal Drug Enforcement Administration agents arrested Dr. Nathan Kuemmerle, 37, of Hollywood, for allegedly writing thousands of prescriptions for highly addictive drugs such as Adderall and Xanax for patients he did not examine, and who allegedly paid cash for the prescriptions. The office manager, Antonie “Tony” Phillips, 28, of Koreatown, was also arrested without incident at Kuemmerle’s clinic at 8235 Santa Monica Blvd.

Both men were charged in a federal criminal complaint filed last Friday. They face up to 20 years in federal prison upon conviction.

The arrests follow a joint investigation by the Redondo Beach Police Department and the DEA’s Tactical Diversion Squad. Kuemmerle allegedly admitted patients to his clinic without appointments, wrote prescriptions during meetings that lasted only a few minutes, and accepted cash payments.

Officials allege that Kuemmerle was running a “pill mill” from the beginning of 2006 through late November 2009. During that period, Kuemmerle wrote 14,529 prescriptions for a variety of controlled substances, including the highest number of prescriptions for Adderall of any physician in California. Kuemmerle was also found to be the state’s second-largest prescriber of all Schedule II drugs, which include amphetamine salts, oxycodone, hydrocodone (Vicodin and Norco), and alprazolam (Xanax).