Marijuana use, disorders doubled since 2001

Before you go, we thought you'd like these...
U.S. Marijuana Arrests Increase Despite Changing Views

(Reuters Health) - As attitudes and laws in the U.S. have become more tolerant of marijuana, the proportion of adults using and abusing the substance at least doubled between 2001 and 2013, according to a new study.

Although marijuana dependence and abuse was found to be on the rise, that is largely due to the overall increase in new users, researchers note, while existing marijuana users experienced a 15 percent decline in pot-related disorders.

SEE ALSO: Conspiracy theories fill Italy media over pope brain tumor story

About 4 percent of adults between 2001 and 2002 reported having used marijuana in the past year, compared to about 10 percent between 2012 and 2013. Similarly, 1.5 percent had abuse or dependence problems - so-called marijuana use disorder - at the start of the 21st Century, compared to about 3 percent from 2012 to 2013.

"What was quite clear is the prevalence of use among adults had more than doubled," said Deborah Hasin, the study's lead author from Columbia University in New York.

Twenty-three U.S. states allow for medical marijuana use, and four also allow recreational use, the researchers write in JAMA Psychiatry. More Americans also favor marijuana legalization than before, and fewer see the substance as risky.

Yet, the researchers write, little was known about how the prevalence of marijuana use and disorders changed during the first decade of the century.

For the new study, they compared data from face-to-face interviews with over 43,000 U.S. adults between 2001 and 2002 to data from over 36,000 people collected between 2012 and 2013.

They found that reports of having used marijuana in the past year more than doubled between the two time periods with especially large increases among women, blacks, Hispanics, southerners and middle-aged and older people.

The data also included information on whether participants were experiencing abuse or dependence.

Between the two time periods, the researchers found that such disorders were about twice as common during the 2012 and 2013 interviews. About three of every 10 marijuana users - about 7 million Americans - were diagnosed with a marijuana use disorder in the latter survey, they write.

Past studies have tied marijuana use to mental health issues, poor quality of life, use of other drugs and withdrawal after heavy use, they add.

Earlier this year, the American Academy of Pediatrics restated their opposition to marijuana legalization based on its well-documented negative effects on the developing brains of children and adolescents, such as impaired memory and problem solving (see Reuters Health story of January 26).

READ MORE: Five things to expect for winter weather

"Counteracting the perceptions that (marijuana) is harmless with a balanced message about the potential harms is important," Hasin told Reuters Health. "For researchers, I think it's important to find what characteristics put people at risk."

"People should consider this information when they're making choices about using marijuana, and the public should consider the information as they consider legalization," Hasin said.

RELATED GALLERY: See pics from the Denver marijuana stoner holiday 2015

22 PHOTOS
Denver pot marijuana stoner holiday 2015
See Gallery
Marijuana use, disorders doubled since 2001
DENVER, CO - APRIL 19: A man exhales marijuana smoke during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Kimberly Bullard, 23, of Los Angeles, California takes a hit off a I420 Double Barrel Shotgun pipe during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: A man raises a lighter and joint to the sky just before 4:20 during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: A woman sports a marijuana leaf hat during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: A man takes a selfie as he smokes a joint during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Frank Froman takes a hit from the I420 Double Barrel Shotgun pipe by Incredibowl being held by Rolf Johnson, 26, during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Smoke rolls off the end of a dab rig during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Attendees do dabs during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Attendees look over a selection of marijuana themed shirts during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Mindie Flores weighs out a gram of Moon Rocks at the Kurrupt's Moon Rocks booth during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Shawn Holland, 21, takes a rip off a gas mask bong during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Harmony Johnson of Boulder rocks a marijuana leaf hat during Denver's annual 4/20 festival at Civic Center Park on Sunday, April 19, 2015. Thousands of people gathered to watch a free Rick Ross concert, while partaking in the day's goods and services. (Photo by AAron Ontiveroz/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Shawn Holland, 21, breaks up a piece of marijuana to roll a joint during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Shawn Holland, 21, blows on the end of a tulip joint while smoking it during the High Times Cannabis Cup at the Denver Mart in Denver, Colorado on April 19, 2015. The High Times Cannabis Cup runs through Monday at the Denver Mart. (Photo by Seth McConnell/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Stephanie Hodge reacts to smoking from a gas mask marijuana smoking apparatus during Denver's annual 4/20 festival at Civic Center Park on Sunday, April 19, 2015. Thousands of people gathered to watch a free Rick Ross concert, while partaking in the day's goods and services. (Photo by AAron Ontiveroz/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Dakota Wallin of Littleton smokes a half-ounce joint during Denver's annual 4/20 festival at Civic Center Park on Sunday, April 19, 2015. Thousands of people gathered to watch a free Rick Ross concert, while partaking in the day's goods and services. (Photo by AAron Ontiveroz/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Stephanie Hodge smokes a gas mask marijuana smoking apparatus during Denver's annual 4/20 festival at Civic Center Park on Sunday, April 19, 2015. Thousands of people gathered to watch a free Rick Ross concert, while partaking in the day's goods and services. (Photo by AAron Ontiveroz/The Denver Post via Getty Images)
DENVER, CO - APRIL 19: Kris Custer waves a marijuana leaf flag during Denver's annual 4/20 festival at Civic Center Park on Sunday, April 19, 2015. Thousands of people gathered to watch a free Rick Ross concert, while partaking in the day's goods and services. (Photo by AAron Ontiveroz/The Denver Post via Getty Images)
Partygoers listen to music and smoke marijuana on one of several days of the annual 4/20 marijuana festival, in Denver's downtown Civic Center Park, Saturday April 18, 2015. The annual event is the second 4/20 marijuana celebration since retail marijuana stores began selling in January 2014. (AP Photo/Brennan Linsley)
Partygoers listen to music and smoke marijuana on one of several days of the annual 4/20 marijuana festival, in Denver's downtown Civic Center Park, Saturday April 18, 2015. The annual event is the second 4/20 marijuana celebration since retail marijuana stores began selling in January 2014. (AP Photo/Brennan Linsley)
Partygoers listen to music and smoke marijuana on one of several days of the annual 4/20 marijuana festival, in Denver's downtown Civic Center Park, Saturday, April 18, 2015. The annual event is the second 4/20 marijuana celebration since retail marijuana stores began selling in January 2014. (AP Photo/Brennan Linsley)
Partygoers listen to music and smoke marijuana on one of several days of the annual 4/20 marijuana festival, in Denver's downtown Civic Center Park, Saturday April 18, 2015. The annual event is the second 4/20 marijuana celebration since retail marijuana stores began selling in January 2014. (AP Photo/Brennan Linsley)
of
SEE ALL
BACK TO SLIDE
SHOW CAPTION +
HIDE CAPTION


More from AOL.com:
Google 'leaks' documents on time-traveling car
Israeli soldiers kill Jewish man mistaken for 'terrorist'
Kerry, Netanyahu call for end to incitement amid violence

Read Full Story