Personally I don't know if the isuess related to intelligence from the use of cannabis are a cause or an effect but hey.
"Both adolescent and adult marijuana users reportedly have impaired performance and altered brain activity across several forms of memory. "
Impulsivity, Attention, Memory, and Decision-Making among Adolescent Marijuana Users
Donald M. Dougherty,1,* Charles W. Mathias,1 Michael A. Dawes,1 R. Michael Furr,2 Nora E. Charles,1 Anthony Liguori,3 Erin E. Shannon,3 and Ashley Acheson1
Marijuana is a popular drug of abuse among adolescents, and they may be uniquely vulnerable to resulting cognitive and behavioral impairments. Previous studies have found impairments among adolescent marijuana users. However, the majority of this research has examined measures individually rather than multiple domains in a single cohesive analysis. This study used a logistic regression model that combines performance on a range of tasks to identify which measures were most altered among adolescent marijuana users.
The purpose of this research was to determine unique associations between adolescent marijuana user and performances on multiple cognitive and behavioral domains (attention, memory, decision-making, and impulsivity) in 14- to 17-year-olds while simultaneously controlling for performances across the measures to determine which measures most strongly distinguish marijuana users from non-users.
Marijuana-using adolescents (n=45) and controls (n=48) were tested. Logistic regression analyses were conducted to test for: (a) differences between marijuana users and non-users on each measure, (b) associations between marijuana use and each measure after controlling for the other measures, and (c) the degree to which (a) and (b) together elucidated differences among marijuana users and non-users.
Of all the cognitive and behavioral domains tested, impaired short-term recall memory and consequence sensitivity impulsivity were associated with marijuana use after controlling for performances across all measures.
This study extends previous findings by identifying cognitive and behavioral impairments most strongly associated with adolescent marijuana users. These specific deficits are potential targets of intervention for this at-risk population.