SOURCE : Substance Abuse and Mental Health Services Administration (SAMHSA)  - 2009, age 12 and over

NOTES:

Prohibition touches very little of the drug abuse problem. Moreover, the heavy co-morbidity of alcohol abuse with other drugs suggests that any decrease in use of other drugs might be replaced with more alcohol use. Alcohol may be the most problematic drug because of  its  drug effects  on others.

The figures above show very little  variation since 2002 when SAMHSA began the new system.  This is despite  the addition of over 4 million new  drug users  each year. For every case of new abuse or addiction, someone recovered. 

Marijuana abuse is both numerous and unusual.  This is because it is so popular  (over 100 million lifetime users) relative to other drugs except alcohol. Well over half of marijuana problem use is co-morbid with  alcohol abuse according to NIAAA. The IOM report of 1999 says: “A distinctive marijuana and THC withdrawal syndrome has been identified, but it is mild and subtle compared with the profound physical syndrome of alcohol or heroin withdrawal.” (IOM pp. 89, 90) “Compared to most other drugs ... dependence among marijuana users is relatively rare.” (IOM p. 94) Based  only on reactions to the  drug, marijuana clearly presents less problems for society than alcohol, heroin,  cocaine or strong  stimulants.  

"Methamphetamine ?" indicates the fact that SAMHSA reports  on  "stimulants"  of which meth is  only a part.  The stimulant total was  .37  and the .3?  figure above is probably too high since meth use  has declined over the past few years and is probably  in the range of  .1 to .2 now.  

Pain pills and tranquilizers refer to  prescription drugs used non-medically. SAMHSA reports these as "illicit" drugs.

Crack is thought to account for about a quarter  to a third of total  cocaine problem use. Most  cocaine powder users have never tried crack. 

With the dozens of  drugs that  are less popular it becomes more likely that the users are from an unusual small group that tries almost all of them. They seem to divide into two quite different sub-groups, one that is aware of risks  and  is cautious and controlled  and another  which seems to be on a more desperate search and is highly vulnerable to abuse. Since the numbers are so small it is very hard to get accurate data.

SAMHSA classifies persons as dependent on or abusing specific substances based on criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) from the American Psychiatric Association [APA], 1994. (Work on DSM-V with possibly modified  standards and definitions is in progress.)

Professionals normally refer to these diagnosable drug problems as "substance use disorders" or SUD. 

The PERCENT figures above  may be divided by 10 to get a figure (slightly high)  for the percent of the total US population age 12 and over with SUD  (9 percent).