Author Topic: Marijuana does not cause decline in intelligence among teens - US Researchers  (Read 122 times)

0 Members and 1 Guest are viewing this topic.

Offline admin

  • Administrator
  • Hero Member
  • *****
  • Posts: 1213
    • View Profile

Marijuana does not lead to a decline in intelligence in teenage users, the largest longitudinal study on the drug and IQ change has shown. US researchers looked at more than 3,000 individuals, including twins, measuring cognitive decline of cannabis users compared to non-cannabis users.

Researchers from the University of Southern California, Los Angeles noted that marijuana use in adolescence has previously been associated with reduced intelligence, memory, attention and verbal ability. But whether the drug directly causes cognitive decline, or if there are other factors at play, is unclear.

In their study, published in the journal PNAS, the team looked at the relationship between marijuana use and different measures of intelligence among twins. "Marijuana is the most commonly used recreational drug in the United States," they wrote. "Some studies suggest that marijuana use in adolescence is linked to declines in intellectual functioning. Because of the infeasibility of studying this phenomenon experimentally, it is unclear whether the association can be causally attributed to marijuana use itself or is instead the result of confounding factors."

Measures of intelligence were taken at the ages of between nine and 12, before they started using marijuana, and again at between 17 and 20. Marijuana use was self-reported and the scientists adjusted their results for family background and genetic propensities.

Researchers found that in the first sample (not looking at the twins) marijuana users had lower test scores compared to non-users, and that there had been a "significant decline" in crystallised intelligence (vocabulary and information) between preadolescence and late adolescence.


Researchers discovered potential cancer treatment while seeking malaria vaccine

Started by legendguru

Replies: 0
Views: 192
Last post October 17, 2015, 07:40:50 PM
by legendguru
Researchers Unveil experimental Blood Cancer Therapy with Exciting Results

Started by mastercode

Replies: 0
Views: 132
Last post February 18, 2016, 12:47:20 AM
by mastercode
US Researchers Grows Human Brain in the Lab from Skin Cells [Photo]

Started by mastercode

Replies: 0
Views: 164
Last post August 20, 2015, 02:19:03 PM
by mastercode
Bacteria Can Stop Transmission of Mosquito-borne Illness, Says Researchers

Started by admin

Replies: 0
Views: 235
Last post October 28, 2016, 05:52:36 AM
by admin
Reading May Extend Lifespan - Fresh Study by Researchers

Started by yungcrux

Replies: 0
Views: 178
Last post August 10, 2016, 07:10:25 AM
by yungcrux
Researchers developed USB Stick Device that Measures HIV Levels

Started by legendguru

Replies: 0
Views: 283
Last post November 11, 2016, 12:42:44 AM
by legendguru
Pain Gap' Between Rich, Poor Countries is Alarming - Says Researchers

Started by yungcrux

Replies: 0
Views: 149
Last post October 16, 2017, 12:09:02 AM
by yungcrux
US Researchers to Study Chemical Contamination of US Waters

Started by guruslodge

Replies: 0
Views: 229
Last post August 16, 2017, 12:19:02 AM
by guruslodge
US Researchers Developing New Test for Lyme Disease

Started by naij

Replies: 0
Views: 237
Last post August 18, 2017, 12:44:32 AM
by naij
Not everyone who is infected with HIV goes on to develop AIDS- Researchers

Started by newspostng

Replies: 0
Views: 324
Last post September 30, 2016, 01:26:42 AM
by newspostng