In the last decade, shortages of prescription drugs containing controlled substances, such as narcotics and stimulants, have increased nationwide, preventing providers and patients from accessing essential medications for treatment. Controlled substances are regulated by DEA because of the potential for abuse and addiction. To prevent diversion of controlled substances, DEA sets quotas that limit the amount of certain substances that are available in the United States. This book examines the trends in such shortages; the effect on patients and providers; DEAs administration of the quota process; coordination between DEA and FDA to prevent and mitigate shortages; how DEA manages diversion investigation efforts; and how DEA ensures policies and procedures are followed for investigations and the extent to which it determines the results of its efforts.