Relation between cannabis use and subcortical volumes in people at clinical high risk of psychosis.
Among people at genetic risk of schizophrenia, those who use cannabis show smaller thalamic and hippocampal volumes. We evaluated this relationship in people at clinical high risk (CHR) of psychosis. The Alcohol and Drug Use Scale was used to identify 132 CHR cannabis users, the majority of whom were non-dependent cannabis users, 387 CHR non-users, and 204 healthy control non-users, and all participants completed magnetic resonance imaging scans. Volumes of the thalamus, hippocampus and amygdala were extracted with FreeSurfer, and compared across groups. Comparing all CHR participants with healthy control participants revealed no significant differences in volumes of any ROI. However, when comparing CHR users to CHR non-users, a significant ROI×Cannabis group effect emerged: CHR users showed significantly smaller amygdala compared to CHR non-users. However, when limiting analysis to CHR subjects who reported using alcohol at a 'use without impairment' severity level, the amygdala effect was non-significant; rather, smaller hippocampal volumes were seen in CHR cannabis users compared to non-users. Controlling statistically for effects of alcohol and tobacco use rendered all results non-significant. These results highlight the importance of controlling for residual confounding effects of other substance use when examining the relationship between cannabis use and neural structure.
Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada.
Lisa
L
Buchy
University of California, San Francisco, San Francisco, CA, United States.
Daniel H
DH
Mathalon
Department of Psychology, Yale University, New Haven, CT, United States.
Tyrone D
TD
Cannon
Department of Psychiatry, UCSD, La Jolla, CA, United States.
Kristin S
KS
Cadenhead
Department of Psychiatry, Zucker Hillside Hospital, Long Island, NY, United States.
Barbara A
BA
Cornblatt
Department of Psychiatry, Yale University, New Haven, CT, Unites States.
Thomas H
TH
McGlashan
Department of Psychiatry, University of North Carolina, Chapel Hill, NC, United States.
Diana O
DO
Perkins
Department of Psychiatry, Harvard Medical School at Beth Israel Deaconess Medical Center and Massachusetts General Hospital, Boston, MA, United States.
Larry J
LJ
Seidman
Department of Psychiatry, UCSD, La Jolla, CA, United States.
Ming T
MT
Tsuang
Departments of Psychology and Psychiatry, Emory University, Atlanta, GA, United States.
Elaine F
EF
Walker
Department of Psychiatry, Yale University, New Haven, CT, Unites States.
Scott W
SW
Woods
Departments of Psychiatry and Biobehavioral Sciences and Psychology, UCLA, Los Angeles, CA, United States.
Carrie E
CE
Bearden
Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada. Electronic address: jmadding@ucalgary.ca.
Jean
J
Addington
D000293:Adolescent; D000328:Adult; D000679:Amygdala / Q000473:pathology*; D002188:Cannabis / Q000009:adverse effects*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011618:Psychotic Disorders / Q000473:pathology*; D013788:Thalamus / Q000473:pathology*; D055815:Young Adult
Amygdala; Hippocampus; Magnetic resonance imaging; Marijuana; Neuroanatomy; Schizophrenia; Thalamus