title: Abnormal striatal circuitry and intensified novelty seeking among adolescents who abuse methamphetamine and cannabis.
abstract: It has been hypothesized that changes in striatal-mediated dopamine modulation during adolescence may increase the risk for initiating substance abuse as a result of its fundamental role in arbitrating reward sensitivity and motivation during learning and decision making. However, substance abuse during adolescence may also significantly modify striatal structure and function and concomitantly alter reward sensitivity and action control while this brain region is undergoing remodeling. In the present investigation, to assess the relationship of methamphetamine (Meth) or Meth and cannabis (CA) abuse to regional striatal morphology, we acquired structural magnetic resonance images, using a 3T Siemens Trio scanner, from three groups of adolescents composed of healthy controls (n = 10), Meth abusers (n = 9) and combined Meth and CA abusers (Meth+CA, n = 8). We also assessed novelty seeking using the novelty seeking subscale of Cloninger's Tridimensional Character Inventory. The results indicate that adolescent Meth+CA abusers have increased regional striatal volume and show intensified novelty seeking in contrast to the controls. The degree of Meth exposure was also positively correlated with regional striatal volume and novelty seeking in both the Meth and Meth+CA users. These preliminary findings support theories that propose a role for the striatum in adolescent substance abuse and further indicate that novelty seeking may be related to the initiation of, or sustained, drug use.
authors.affiliation: The Brain Institute, University of Utah, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Churchwell
authors.forename: Paul D
authors.initials: PD
authors.lastname: Carey
authors.forename: Helen L
authors.initials: HL
authors.lastname: Ferrett
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Yurgelun-Todd
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking / Q000453:epidemiology; D019969:Amphetamine-Related Disorders / Q000473:pathology*; D002421:Caudate Nucleus / Q000473:pathology; D002648:Child; D003342:Corpus Striatum / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D002189:Marijuana Abuse / Q000473:pathology*; D008694:Methamphetamine / Q000009:adverse effects*; D009714:Nucleus Accumbens / Q000473:pathology; D009929:Organ Size; D010555:Personality Inventory; D000297:Psychology, Adolescent; D011699:Putamen / Q000473:pathology; D012201:Reward; D012907:Smoking / Q000453:epidemiology
chemical_list: D008694:Methamphetamine