Neuropsychological consequences of regular marijuana use: a twin study.
Psychol Med
; 34(7): 1239-50, 2004 Oct.
Article
de En
| MEDLINE
| ID: mdl-15697050
ABSTRACT
BACKGROUND:
Results of previous research examining long-term residual effects of marijuana use on cognition are conflicting. A major methodological limitation of prior studies is the inability to determine whether differences between users and non-users are due to differences in genetic vulnerability preceding drug use or due to the effects of the drug.METHOD:
Fifty-four monozygotic male twin pairs, discordant for regular marijuana use in which neither twin used any other illicit drug regularly, were recruited from the Vietnam Era Twin Registry. A minimum of 1 year had passed since the marijuana-using twins had last used the drug, and a mean of almost 20 years had passed since the last time marijuana had been used regularly. Twins were administered a comprehensive neuropsychological test battery to assess general intelligence, executive functioning, attention, memory and motor skills. Differences in performance between marijuana-using twins and their non-using co-twins were compared using a multivariate analysis of specific cognitive domains and univariate analyses of individual test scores. Dose response relationships were explored within the marijuana-using group.RESULTS:
Marijuana-using twins significantly differed from their non-using co-twins on the general intelligence domain; however, within that domain only the performance of the block design subtest of the Wechsler Adult Intelligence Scale--Revised reached a level of statistical significance.CONCLUSIONS:
Out of the numerous measures that were administered, only one significant difference was noted between marijuana-using twins and their non-using co-twins on cognitive functioning. The results indicate an absence of marked long-term residual effects of marijuana use on cognitive abilities.
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Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Fumer de la marijuana
/
Abus de marijuana
/
Troubles liés à une substance
/
Maladies chez les jumeaux
/
Tests neuropsychologiques
Limites:
Adult
/
Humans
/
Male
/
Middle aged
Langue:
En
Journal:
Psychol Med
Année:
2004
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique