The impact of initiation: Early onset marijuana smokers demonstrate altered Stroop performance and brain activation.
Marijuana (MJ) use is on the rise, particularly among teens and emerging adults. This poses serious public health concern, given the potential deleterious effects of MJ on the developing brain. We examined 50 chronic MJ smokers divided into early onset (regular MJ use prior to age 16; n=24) and late onset (age 16 or later; n=26), and 34 healthy control participants (HCs). All completed a modified Stroop Color Word Test during fMRI. Results demonstrated that MJ smokers exhibited significantly poorer performance on the Interference subtest of the Stroop, as well as altered patterns of activation in the cingulate cortex relative to HCs. Further, early onset MJ smokers exhibited significantly poorer performance relative to both HCs and late onset smokers. Additionally, earlier age of MJ onset as well as increased frequency and magnitude (grams/week) of MJ use were predictive of poorer Stroop performance. fMRI results revealed that while late onset smokers demonstrated a more similar pattern of activation to the control group, a different pattern was evident in the early onset group. These findings underscore the importance of assessing age of onset and patterns of MJ use and support the need for widespread education and intervention efforts among youth.
Cognitive and Clinical Neuroimaging Core, McLean Imaging Center, McLean Hospital, 115 Mill Street, Belmont, MA 02478, United States. Electronic address: ksagar@mcean.harvard.edu.
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Sagar
Cognitive and Clinical Neuroimaging Core, McLean Imaging Center, McLean Hospital, 115 Mill Street, Belmont, MA 02478, United States. Electronic address: dahlgren@mclean.harvard.edu.
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Dahlgren
Cognitive and Clinical Neuroimaging Core, McLean Imaging Center, McLean Hospital, 115 Mill Street, Belmont, MA 02478, United States; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, United States. Electronic address: ag@mclean.harvard.edu.
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Gönenç
Cognitive and Clinical Neuroimaging Core, McLean Imaging Center, McLean Hospital, 115 Mill Street, Belmont, MA 02478, United States. Electronic address: mracine@mclean.harvard.edu.
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Racine
Cognitive and Clinical Neuroimaging Core, McLean Imaging Center, McLean Hospital, 115 Mill Street, Belmont, MA 02478, United States. Electronic address: mdreman@mclean.harvard.edu.
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Dreman
Cognitive and Clinical Neuroimaging Core, McLean Imaging Center, McLean Hospital, 115 Mill Street, Belmont, MA 02478, United States; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, United States. Electronic address: gruber@mclean.harvard.edu.
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Gruber
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000375:Aging / Q000523:psychology; D001921:Brain / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008385:Marijuana Smoking / Q000503:physiopathology* / Q000523:psychology*; D001523:Mental Disorders / Q000209:etiology / Q000523:psychology; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000187:drug effects; D057190:Stroop Test; D055815:Young Adult
Age of onset; Cognition; Executive function; Marijuana; Stroop; fMRI