Twitter

Jose A. Cortes-Briones
John D. Cahill
Patrick D. Skosnik
Daniel H. Mathalon
Ashley Williams
R. Andrew Sewell
Brian J. Roach
Judith M. Ford
Mohini Ranganathan
Deepak Cyril D’Souza
 
View Article

Abstract
Background
Drugs that induce psychosis may do so by increasing the level of task-irrelevant random neural activity or neural noise. Increased levels of neural noise have been demonstrated in psychotic disorders. We tested the hypothesis that neural noise could also be involved in the psychotomimetic effects of delta-9-tetrahydrocannabinol (Δ9-THC), the principal active constituent of cannabis.
Methods
Neural noise was indexed by measuring the level of randomness in the electroencephalogram during the prestimulus baseline period of an oddball task using Lempel-Ziv complexity, a nonlinear measure of signal randomness. The acute, dose-related effects of Δ9-THC on Lempel-Ziv complexity and signal power were studied in humans (n = 24) who completed 3 test days during which they received intravenous Δ9-THC (placebo, .015 and .03 mg/kg) in a double-blind, randomized, crossover, and counterbalanced design.
Results
THC increased neural noise in a dose-related manner. Furthermore, there was a strong positive relationship between neural noise and the psychosis-like positive and disorganization symptoms induced by Δ9-THC, which was independent of total signal power. Instead, there was no relationship between noise and negative-like symptoms. In addition, Δ9-THC reduced total signal power during both active drug conditions compared with placebo, but no relationship was detected between signal power and psychosis-like symptoms.
Conclusions
At doses that produced psychosis-like effects, Δ9-THC increased neural noise in humans in a dose-dependent manner. Furthermore, increases in neural noise were related with increases in Δ9-THC-induced psychosis-like symptoms but not negative-like symptoms. These findings suggest that increases in neural noise may contribute to the psychotomimetic effects of Δ9-THC.

Twitter

Yuyan Shi1*, Michela Lenzi2, Ruopeng An3
1 Department of Family Medicine and Public Health, University of California San Diego, La Jolla, California,
United States of America, 2 Department of Developmental and Social Psychology, University of Padova,
Padua, Italy, 3 Department of Kinesiology and Community Health, University of Illinois at Urbana-
Champaign, Champaign, Illinois, United States of America
 
Aims
To assess the associations between types of cannabis control policies at country level and prevalence of adolescent cannabis use.
 
Conclusions
Cannabis liberalization with depenalization and partial prohibition policies was associated with higher levels of regular cannabis use among adolescents. The correlations were heterogeneous between genders and between short- and long-terms.
 
For complete article see PDF

Twitter

Examining Linkages with Criminal Behavior
and Psychopathic Features into the Mid-30s

Dustin Pardini ⁽¹⁾
Jordan Bechtold ⁽¹⁾
Rolf Loeber ^(1,2)
Helene White ⁽³⁾

<sub>1. Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
2. Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA
3. Center of Alcohol Studies/Department of Sociology, Rutgers University, Piscataway, NJ, USA</sub>
 

Dustin Pardini, Department of Psychiatry, University of Pittsburgh Medical Center, Sterling Plaza, Suite 408, 201 North Craig Street, Pittsburgh, PA 15213, USA. Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Objectives: Examine whether young men who chronically use marijuana are at risk for engaging in drug-related and non-drug-related criminal offending and exhibiting psychopathic personality features in their mid-30s.

Methods: Patterns of marijuana use were delineated in a sample of predominately Black and White young men from adolescence to the mid-20s using latent class growth curve analysis. Self-report and official records of criminal offending and psychopathic personality features were assessed in the mid-30s. Analyses controlled for multiple factors indicative of a pre-existing antisocial lifestyle and co-occurring use of other substances and tested for moderation by race.

Results: Four latent marijuana trajectory groups were identified: chronic high, adolescence-limited, late increasing, and low/nonusers. Relative to low/nonusers, chronic high and late increasing marijuana users exhibited more adult psychopathic features and were more likely to engage in drug-related offending during their mid-30s. Adolescence-limited users were similar to low/nonusers in terms of psychopathic features but were more likely to be arrested for drug-related crimes. No trajectory group differences were found for violence or theft, and the group differences were not moderated by race.

Conclusions: Young men who engage in chronic marijuana use from adolescence into their 20s are at increased risk for exhibiting psychopathic features, dealing drugs, and enduring drug-related legal problems in their mid-30s relative to men who remain abstinent or use infrequently.

read complete paper

Twitter

No 'Sound Evidence' to Support Use of Cannabinoids for rheumatic diseases”

Diedtra Henderson November 10, 2015
There is "no sound evidence" for clinicians to recommend that patients with rheumatic diseases take cannabinoid treatments, according to a review published online November 9 in Arthritis Care & Research. However, the authors suggest there is merit to further research on cannabinoids' effect on pain and sleep in these conditions.
A systematic review of research since 1940 uncovered few studies examining the effects of cannabinoids in rheumatic diseases, according to Mary-Ann Fitzcharles, MD, from the Division of Rheumatology and Alan Edwards Pain Management Unit, McGill University Health Centre, Quebec, Canada, and colleagues. "Amongst a vast array of rheumatic conditions, cannabinoid effects have only been studied in [rheumatoid arthritis], [fibromyalgia,] and [osteoarthritis], with the latter study prematurely terminated due to lack of efficacy," they write.
Moreover, the authors judged all of the studies included in the analysis as having a high risk of bias, and all had extremely low numbers of participants, suggesting "the possibility that results may be completely random."
Read Complete Article