Evidence map›Paper›PMID 26787878›Full record

ArticleProceedings of the National Academy of Sciences of the United States of America2016

Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies.

Nicholas J Jackson, Joshua D Isen, Rubin Khoddam, Daniel Irons, Catherine Tuvblad, William G Iacono, Matt McGue, Adrian Raine, Laura A Baker

Abstract readTwin Study
PubMed Full text at PMC Publisher
In one paragraph

Article in Proceedings of the National Academy of Sciences of the United States of America, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 89 papers, 7 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
89citing papers in PubMed, 7 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

89 citing papers in PubMed, 7 syntheses or guidelines pooled it.

  1. Pooled it
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  8. Acute effects of different types of cannabis on young adult and adolescent resting-state brain networks.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2024
    Trial
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  20. Medicinal Cannabis for Paediatric Developmental, Behavioural and Mental Health Disorders.International journal of environmental research and public health · 2023
    Review

29 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors.

Nicholas J JacksonDepartment of Psychology, University of Southern California, Los Angeles, CA 90089; Department of Medicine Statistics Core, University of California, Los Angeles, CA 90024;ORCID http://orcid.org/0000-0002-9515-5050
Joshua D IsenDepartment of Psychology, University of Minnesota, Minneapolis, MN 55455; jdisen@umn.edu.
Rubin KhoddamDepartment of Psychology, University of Southern California, Los Angeles, CA 90089;
Daniel IronsDepartment of Psychology, University of Minnesota, Minneapolis, MN 55455;
Catherine TuvbladDepartment of Psychology, University of Southern California, Los Angeles, CA 90089; School of Law, Psychology and Social Work, Örebro University, 702 81 Örebro, Sweden;
William G IaconoDepartment of Psychology, University of Minnesota, Minneapolis, MN 55455;
Matt McGueDepartment of Psychology, University of Minnesota, Minneapolis, MN 55455;
Adrian RaineDepartment of Criminology, University of Pennsylvania, Philadelphia, PA 19104; Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104; Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104.
Laura A BakerDepartment of Psychology, University of Southern California, Los Angeles, CA 90089;

Funding

TWIN STUDY OF FEMALE ALCOHOLISMS AND OTHER DISORDERSR01AA009367 · NIAAA · UNIVERSITY OF MINNESOTA TWIN CITIES · PI MCGUE, MATTHEW K. · 1992 to 2013
$9.0M
RISK FACTORS FOR ANTISOCIAL BEHAVIORR01MH058354 · NIMH · UNIVERSITY OF SOUTHERN CALIFORNIA · PI BAKER, LAURA A · 2000 to 2013
$8.5M
Twin Family Study of Vulnerability to Substance AbuseR37DA005147 · NIDA · UNIVERSITY OF MINNESOTA · PI IACONO, WILLIAM G. · 2009 to 2018
$6.4M
TWIN/FAMILY STUDY OF VULNERABILITY TO SUBSTANCE ABUSER01DA005147 · NIDA · UNIVERSITY OF MINNESOTA TWIN CITIES · PI IACONO, WILLIAM G · 1987 to 2007
$5.5M
Adolescent drinking and midlife outcomes: A prospective cotwin control studyR37AA009367 · NIAAA · UNIVERSITY OF MINNESOTA · PI MCGUE, MATTHEW K. · 2016 to 2024
$5.4M
TWIN STUDY OF ADHD, CD, AND SUBSTANCE ABUSER01DA013240 · NIDA · UNIVERSITY OF MINNESOTA TWIN CITIES · PI IACONO, WILLIAM G. · 2000 to 2010
$5.0M
Adult consequences of youth substance use: Twin study enriched for SUD riskR01DA036216 · NIDA · UNIVERSITY OF MINNESOTA · PI IACONO, WILLIAM G. · 2013 to 2017
$3.2M
Substance Use and Problem Behavior Trajectories across AdolescenceF31DA039708 · NIDA · UNIVERSITY OF SOUTHERN CALIFORNIA · PI KHODDAM, RUBIN · 2015 to 2017
$102k
NIAAA NIH HHS AA 09367NIAAA NIH HHS R01 AA009367NIAAA NIH HHS R37 AA009367NIDA NIH HHS DA 013240NIDA NIH HHS DA036216NIDA NIH HHS DA 05147NIDA NIH HHS F31 DA039708NIDA NIH HHS R01 DA005147NIDA NIH HHS R01 DA013240NIDA NIH HHS R01 DA036216NIDA NIH HHS R37 DA005147NIMH NIH HHS R01 MH058354NIMH NIH HHS R01-MH58354
6 · The paper itself

Abstract

Marijuana is one of the most commonly used drugs in the United States, and use during adolescence--when the brain is still developing--has been proposed as a cause of poorer neurocognitive outcome. Nonetheless, research on this topic is scarce and often shows conflicting results, with some studies showing detrimental effects of marijuana use on cognitive functioning and others showing no significant long-term effects. The purpose of the present study was to examine the associations of marijuana use with changes in intellectual performance in two longitudinal studies of adolescent twins (n = 789 and n = 2,277). We used a quasiexperimental approach to adjust for participants' family background characteristics and genetic propensities, helping us to assess the causal nature of any potential associations. Standardized measures of intelligence were administered at ages 9-12 y, before marijuana involvement, and again at ages 17-20 y. Marijuana use was self-reported at the time of each cognitive assessment as well as during the intervening period. Marijuana users had lower test scores relative to nonusers and showed a significant decline in crystallized intelligence between preadolescence and late adolescence. However, there was no evidence of a dose-response relationship between frequency of use and intelligence quotient (IQ) change. Furthermore, marijuana-using twins failed to show significantly greater IQ decline relative to their abstinent siblings. Evidence from these two samples suggests that observed declines in measured IQ may not be a direct result of marijuana exposure but rather attributable to familial factors that underlie both marijuana initiation and low intellectual attainment.

Indexed as

IntelligenceMarijuana SmokingAdolescentChildFemaleHumansLongitudinal StudiesMaleadolescenceintelligencelongitudinalmarijuana usetwins

Identifiers

PMID26787878
PMCPMC4747759

What OpenQuestion holds

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Read underepoch 390

Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.