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Background: The effect of concomitant cocaine and cannabis use on monocyte activation and inflammation in patients with alcohol use disorder (AUD) is unknown., Methods: To analyze the impact of cocaine and cannabis use on levels of markers of monocyte activation (sCD163 and sCD14) and systemic inflammation (interleukin-6 [IL-6]) in AUD patients admitted for hospital treatment between 2013 and 2018. Clinical and laboratory parameters were obtained upon admission. IL-6, sCD163, and sCD14 were measured in frozen plasma samples. We performed logistic regression to detect associations between cocaine and cannabis use and markers of monocyte activation and inflammation in the highest quartile., Results: A total of 289 patients (77.5 % male) were included (median age = 50 years). The median alcohol intake upon admission was 142 g/day. The median duration of AUD was 20 years. Of the 289 patients with AUD, 76 % were active smokers, 23.1 % and 22.1 % concomitantly used cocaine and cannabis, respectively The median levels of IL-6, sCD163, and sCD14 were 4.37 pg/mL, 759 ng/mL, and 1.68 × 10 6 pg/mL, respectively. We did not detect associations between cocaine use and inflammation or monocyte activation. Cannabis use was associated with a higher odds of having sCD163 levels in the highest quartile (adjusted odds ratio = 2.34, 95 % confidence interval = 1.07-5.15, p = 0.03). Cannabis use was not associated with inflammation., Conclusion: In this series of AUD patients the concomitant use of cannabis use was associated with sCD163 levels that were in the highest quartile, consistent with monocyte activation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Although the incidence of cannabis abuse/dependence in Americans is rising, the neurobiology of cannabis addiction is not well understood. Imaging studies have demonstrated deficits in striatal D(2)/D(3) receptor availability in several substance-dependent populations. However, this has not been studied in currently using chronic cannabis users., Objective: The purpose of this study was to compare striatal D(2)/D(3) receptor availability between currently using chronic cannabis users and healthy controls., Methods: Eighteen right-handed males age 18-34 were studied. Ten subjects were chronic cannabis users; eight were demographically matched controls. Subjects underwent a [(11)C]raclopride (RAC) PET scan. Striatal RAC binding potential (BP(ND)) was calculated on a voxel-wise basis. Prior to scanning, urine samples were obtained from cannabis users for quantification of urine Δ-9-tetrahydrocannabinol (THC) and THC metabolites (11-nor-Δ-9-THC-9-carboxylic acid; THC-COOH and 11-hydroxy-THC;OH-THC)., Results: There were no differences in D(2)/D(3) receptor availability between cannabis users and controls. Voxel-wise analyses revealed that RAC BP(ND) values were negatively associated with both urine levels of cannabis metabolites and self-report of recent cannabis consumption., Conclusions: In this sample, current cannabis use was not associated with deficits in striatal D(2)/D(3) receptor availability. There was an inverse relationship between chronic cannabis use and striatal RAC BP(ND). Additional studies are needed to identify the neurochemical consequences of chronic cannabis use on the dopamine system., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background: Marijuana use is typically initiated during adolescence, which is a critical period for neural development. Studies have reported reductions in prepulse inhibition (PPI) among adults who use marijuana chronically, although no human studies have been conducted during the critical adolescent period., Methods: This study tested PPI of acoustic startle among adolescents who were either frequent marijuana users or naïve to the drug (Controls). Adolescents were tested using two intensities of prepulses (70 and 85 dB) combined with a 105 dB startle stimulus, delivered across two testing blocks., Results: There was a significant interaction of group by block for PPI; marijuana users experienced a greater decline in the PPI across the testing session than Controls. The change in PPI of response magnitude for users was predicted by change in urine THC/creatinine after at least 18 h of abstinence, the number of joints used during the previous week before testing, as well as self-reported DSM-IV symptoms of marijuana tolerance, and time spent using marijuana rather than participating in other activities., Conclusions: These outcomes suggest that adolescents who are frequent marijuana users have problems maintaining prepulse inhibition, possibly due to lower quality of information processing or sustained attention, both of may contribute to continued marijuana use as well as attrition from marijuana treatment., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Marijuana is the most widely used illicit substance in the United States; however, previous imaging studies have not detected altered brain structure in marijuana users compared to non-users. Voxel-based morphometry was used to investigate possible differences in brain tissue composition in a group of 11 heavy marijuana users and a group of 8 non-users. All participants were male. Statistical comparisons were made at the voxel level on T1-weighted magnetic resonance images to determine differences in gray matter and white matter tissue density. Compared to non-users, marijuana users had lower gray matter density in a cluster of voxels in the right parahippocampal gyrus (P = 0.0001), and greater density bilaterally near the precentral gyrus and the right thalamus (P < 0.04). Marijuana users also had lower white matter density in the left parietal lobe (P = 0.03), and higher density around the parahippocampal and fusiform gyri on the left side compared to non-users (P < 0.002). Longer duration of marijuana use (in years) was significantly correlated with higher white matter tissue density in the left precentral gyrus (P = 0.045). Our preliminary results suggest evidence of possible structural differences in the brain of heavy marijuana users, and localize regions for further investigation of the effects of marijuana in the brain.