title: Marijuana effects on changes in brain structure and cognitive function among HIV+ and HIV- adults.
abstract: The current study examined the independent and interactive effects of HIV and marijuana (MJ) use on brain structure and cognitive function among a sample of HIV-positive (HIV+) and HIV-negative (HIV-) individuals.
  
  
  
  Participants (HIV+, n=48; HIV-, n=29) individuals underwent cognitive testing, questionnaires about substance use, and brain MRI. The HIV+ group was clinically stable based upon current plasma CD4 count, 50% had undetectable viral load (i.e.,<20 copies/mL), and all were on a stable regimen of cART.
  
  
  
  For HIV+ and HIV- participants, higher levels of MJ use were associated with smaller volumes in the entorhinal cortex and fusiform gyrus. HIV status (but not MJ use) was associated with cingulate thickness, such that HIV+ participants evidenced smaller thickness of the cingulate, as compared to HIV- controls. Regarding neurocognitive functioning, there was a HIV*MJ interactive effect on global cognition, such that when the amount of MJ use was less than 1.43g per week, the HIV- group displayed significantly better neurocognitive performance than the HIV+ group (t=3.14, p=0.002). However, when MJ use reached 1.43g per week, there were no significant HIV group differences in global cognitive performance (t=1.39, p=0.168).
  
  
  
  Our results show independent and interactive effects of HIV and MJ on brain structure and cognition. However, our results do not support that HIV+ MJ users are at greater risk for adverse brain or cognitive outcomes compared to HIV- MJ users.
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, 740 Westwood Plaza 28-263, Los Angeles, CA 90095, USA. Electronic address: athames@mednet.ucla.edu.
authors.forename: April D
authors.initials: AD
authors.lastname: Thames
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, 740 Westwood Plaza 28-263, Los Angeles, CA 90095, USA.
authors.forename: Taylor P
authors.initials: TP
authors.lastname: Kuhn
authors.affiliation: Department of Psychology, University of California Los Angeles, Franz Hall, 502 Portola Plaza, Los Angeles, CA 90095, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Williamson
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, 740 Westwood Plaza 28-263, Los Angeles, CA 90095, USA.
authors.forename: Jacob D
authors.initials: JD
authors.lastname: Jones
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, 740 Westwood Plaza 28-263, Los Angeles, CA 90095, USA.
authors.forename: Zanjbeel
authors.initials: Z
authors.lastname: Mahmood
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, 740 Westwood Plaza 28-263, Los Angeles, CA 90095, USA; Department of Psychology, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Hammond
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects*; D002186:Cannabinoids / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects*; D005260:Female; D015658:HIV Infections / Q000000981:diagnostic imaging* / Q000523:psychology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008385:Marijuana Smoking / Q000473:pathology / Q000523:psychology*; D008875:Middle Aged; D019562:Viral Load; D055815:Young Adult
chemical_list: D002186:Cannabinoids
keywords: Cannabis; Cognition; HIV; Magnetic resonance imaging; Marijuana