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Updated: Oct 28, 2025

Brain Morphology of Cannabis Users With or Without Psychosis: A Pilot MRI Study
Published on: August 18, 2020
The Alerting and Orienting Systems of Attention Are Modified by Cannabis Dependence
Ivett E Ortega-Mora1, Ulises Caballero-Sánchez1, Talía V Román-López1
1Grupo de Neurociencias: Lab. Neurogenómica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicología, Av. Universidad 3004, Col. UNAM, C.P. 04510, Universidad Nacional Autónoma de México (UNAM), Mexico.
Abstract:
Attention allows us to select relevant information from the background. Although several studies have described that cannabis use induces deleterious effects on attention, it remains unclear if cannabis dependence affects the attention network systems differently.
Objectives:
To evaluate whether customary consumption of cannabis or cannabis dependence impacts the alerting, orienting, and executive control systems in young adults; to find out whether it is related to tobacco or alcohol dependence and if cannabis use characteristics are associated with the attention network systems.
Method:
One-hundred and fifty-four healthy adults and 102 cannabis users performed the Attention Network Test (ANT) to evaluate the alerting, orienting, and executive control systems.
Results:
Cannabis use enhanced the alerting system but decreased the orienting system. Moreover, those effects seem to be associated with cannabis dependence. Out of all the cannabis-using variables, only the age of onset of cannabis use significantly predicted the efficiency of the orienting and executive control systems.
Conclusion:
Cannabis dependence favors tonic alertness but reduces selective attention ability; earlier use of cannabis worsens the efficiency of selective attention and resolution of conflicts.
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