title: Altered Neural Processing to Social Exclusion in Young Adult Marijuana Users.
abstract: Previous studies have reported that peer groups are one of the most important predictors of adolescent and young adult marijuana use, and yet the neural correlates of social processing in marijuana users have not yet been studied. In the current study, marijuana-using young adults (n = 20) and non-using controls (n = 22) participated in a neuroimaging social exclusion task called Cyberball, a computerized ball-tossing game in which the participant is excluded from the game after a pre-determined number of ball tosses. Controls, but not marijuana users, demonstrated significant activation in the insula, a region associated with negative emotion, when being excluded from the game. Both groups demonstrated activation of the ventral anterior cingulate cortex (vACC), a region associated with affective monitoring, during peer exclusion. Only the marijuana group showed a correlation between vACC activation and scores on a self-report measure of peer conformity. This study indicates that marijuana users show atypical neural processing of social exclusion, which may be either caused by, or the result of, regular marijuana use.
authors.affiliation: Center for Addiction Medicine, Massachusetts General Hospital (MGH) Department of Psychiatry, Boston, MA; Athinoula A. Martinos Center in Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA.
authors.forename: Jodi M
authors.initials: JM
authors.lastname: Gilman
authors.affiliation: Center for Addiction Medicine, Massachusetts General Hospital (MGH) Department of Psychiatry, Boston, MA.
authors.forename: Max T
authors.initials: MT
authors.lastname: Curran
authors.affiliation: Center for Addiction Medicine, Massachusetts General Hospital (MGH) Department of Psychiatry, Boston, MA.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Calderon
authors.affiliation: Center for Addiction Medicine, Massachusetts General Hospital (MGH) Department of Psychiatry, Boston, MA; Harvard Medical School, Boston, MA, USA.
authors.forename: Randi M
authors.initials: RM
authors.lastname: Schuster
authors.affiliation: Center for Addiction Medicine, Massachusetts General Hospital (MGH) Department of Psychiatry, Boston, MA; Harvard Medical School, Boston, MA, USA.
authors.forename: A Eden
authors.initials: AE
authors.lastname: Evins
keywords: ACC; Social Influence; anterior cingulate cortex; cannabis; exclusion; insula; marijuana; peer groups