SAMSHA reports:
Approximately 21.5 million people aged 12 or older in 2014 had a substance use disorder (SUD) in the past year, including 17.0 million people with an alcohol use disorder, 7.1 million with an illicit drug use disorder, and 2.6 million who had both an alcohol use and an illicit drug use disorder

The National Institute On Drug Abuse states:
‘The goal of treatment is to return people to productive functioning in the family, workplace, and community. According to research that tracks individuals in treatment over extended periods, most people who get into and remain in treatment stop using drugs, decrease their criminal activity, and improve their occupational, social, and psychological functioning.

It has been known for many years that the “treatment gap” is massive—that is, among those who need treatment for a substance use disorder, few receive it. In 2011, 21.6 million persons aged 12 or older needed treatment for an illicit drug or alcohol use problem, but only 2.3 million received treatment at a specialty substance abuse facility.’

According to The New York Times in the Aug. 15, 2018, issue:
Drug overdoses killed about 72,000 Americans last year, a record number that reflects a rise of around 10 percent, according to new preliminary estimates from the Centers for Disease Control. The death toll is higher than the peak yearly death totals from H.I.V., car crashes or gun deaths.

This quote is from a new book called Dopesick, Dealers, Doctors, and the Drug Company that Addicted America, by Beth Macy:

Drug overdose had already taken the lives of 300,000 Americans over the past fifteen years, and experts now predicted that 300,000 would die in only the next five. It is now the leading cause of death for Americans under the age of fifty, killing more people than guns or car accidents, at a rate higher than the HIV epidemic at its peak.