Quote (Microbiologist @ Mon, Aug 24 2009, 11:25am)
"Cannabis does not cause addiction"
First positive reactions to cannabis constitute a priority risk factor for cannabis dependence.
Addiction. 2009 Aug 7.
Le Strat Y, Ramoz N, Horwood J, Falissard B, Hassler C, Romo L, Choquet M, Fergusson D, Gorwood P.
INSERM U675-U894, Centre Psychiatrie et Neurosciences, Université Paris V, Paris, France.
Aim To assess the association between first reactions to cannabis and the risk of cannabis dependence. Design A cross-sectional population-based assessment in 2007. Setting A campus in a French region (Champagne-Ardennes). Participants A total of 1472 participants aged 18-21 years who reported at least one life-time cannabis consumption, of 3056 students who were screened initially [the Susceptibility Addiction Gene Environment (SAGE) study]. Measurements Positive and negative effects of first cannabis consumptions, present cannabis dependence and related risk factors were assessed through questionnaires. Findings The effects of first cannabis consumptions were associated dose-dependently with cannabis dependence at age 18-21 years, both according to the transversal approach of the SAGE study and to the prospective cohort of the Christchurch Health and Development Study (CHDS) assessed at the age of 25 years. Participants of the SAGE study who reported five positive effects of their first cannabis consumption had odds of life-time cannabis dependence that were 28.7 (95% confidence interval: 14.6-56.5) higher than those who reported no positive effects. This association remains significant after controlling for potentially confounding factors, including individual and familial variables. Conclusions This study suggests an association between positive reactions to first cannabis uses and risk of life-time cannabis dependence, this variable having a central role among, and through, other risk factors.
Marijuana craving in the brain.
Proc Natl Acad Sci U S A. 2009 Aug 4;106(31):13016-21. Epub 2009 Jul 27.
Filbey FM, Schacht JP, Myers US, Chavez RS, Hutchison KE.
The Mind Research Network, 1101 Yale Boulevard, Albuquerque, NM 87106, USA. ffilbey@mrn.org
Craving is one of the primary behavioral components of drug addiction, and cue-elicited craving is an especially powerful form of this construct. While cue-elicited craving and its underlying neurobiological mechanisms have been extensively studied with respect to alcohol and other drugs of abuse, the same cannot be said for marijuana. Cue-elicited craving for other drugs of abuse is associated with increased activity in a number of brain areas, particularly the reward pathway. This study used functional magnetic resonance imaging (fMRI) to examine cue-elicited craving for marijuana. Thirty-eight regular marijuana users abstained from use for 72 h and were presented with tactile marijuana-related and neutral cues while undergoing a fMRI scan. Several structures in the reward pathway, including the ventral tegmental area, thalamus, anterior cingulate, insula, and amygdala, demonstrated greater blood oxygen level dependent (BOLD) activation in response to the marijuana cue as compared with the neutral cue. These regions underlie motivated behavior and the attribution of incentive salience. Activation of the orbitofrontal cortex and nucleus accumbens was also positively correlated with problems related to marijuana use, such that greater BOLD activation was associated with greater number of items on a marijuana problem scale. Thus, cue-elicited craving for marijuana activates the reward neurocircuitry associated with the neuropathology of addiction, and the magnitude of activation of these structures is associated with severity of cannabis-related problems. These findings may inform the development of treatment strategies for cannabis dependence.
"Cannabis is good for your health"
Long-term consequences of adolescent cannabis exposure on the development of cognition, brain structure and function: an overview of animal and human research.
Curr Drug Abuse Rev. 2008 Jun;1(2):114-23.
Jager G, Ramsey NF.
Rudolf Magnus Institute of Neuroscience, Department of Neurology and Neurosurgery, University Medical Center Utrecht, The Netherlands. gjager@umcutrecht.nl
Over the last decade there has been a steady increase in the prevalence of frequent cannabis use among teenagers, accompanied by a decrease in age of first use. Evidence from both animal and human studies suggests that the severity of the effects of cannabis use on cognitive development is dependent on the age when cannabis use begins. One possible explanation is that those who begin cannabis use early in adolescence are more likely to become heavily dependent. It is plausible that chronic cannabis abuse will then interfere with educational and vocational training. From a more biological perspective, however, use of cannabis during critical developmental periods in the still maturing brain may induce persistent alterations in brain structure and brain function. Therefore, the effects of frequent cannabis use during adolescence could be different from and more serious than during adulthood, an issue increasingly recognized in the field of cannabis research. In this paper we review the relevant animal and human literature on long-term effects of frequent exposure to cannabis during adolescence on the development of cognition, brain structure and function, and discuss implications, methodological and conceptual issues, and future prospects.
Role of cannabis and endocannabinoids in the genesis of schizophrenia.
Psychopharmacology (Berl). 2009 Jul 24.
Fernandez-Espejo E, Viveros MP, Núñez L, Ellenbroek BA, Rodriguez de Fonseca F.
Departamento de Fisiología Médica, Facultad de Medicina, Universidad de Sevilla, 41009, Seville, Spain, efespejo@us.es.
RATIONALE: Cannabis abuse and endocannabinoids are associated to schizophrenia. OBJECTIVES: It is important to discern the association between schizophrenia and exogenous Cannabis sativa, on one hand, and the endogenous cannabinoid system, on the other hand. RESULTS: On one hand, there is substantial evidence that cannabis abuse is a risk factor for psychosis in genetically predisposed people, may lead to a worse outcome of the disease, or it can affect normal brain development during adolescence, increasing the risk for schizophrenia in adulthood. Regarding genetic predisposition, alterations affecting the cannabinoid CNR1 gene could be related to schizophrenia. On the other hand, the endogenous cannabinoid system is altered in schizophrenia (i.e., increased density of cannabinoid CB1 receptor binding in corticolimbic regions, enhanced cerebrospinal fluid anandamide levels), and dysregulation of this system can interact with neurotransmitter systems in such a way that a "cannabinoid hypothesis" can be integrated in the neurobiological hypotheses of schizophrenia. Finally, there is also evidence that some genetic alterations of the CNR1 gene can act as a protectant factor against schizophrenia or can induce a better pharmacological response to atypical antipsychotics. CONCLUSIONS: Cannabis abuse is a risk factor for psychosis in predisposed people, it can affect neurodevelopment during adolescence leading to schizophrenia, and a dysregulation of the endocannabinoid system can participate in schizophrenia.
cool arguments, but im pretty sure no one thinks weed isnt addictive as it clearly is, and im also sure no one here thinks its good for your health, as obviously inhaling smoke into your lungs, no matter where it comes from isnt good for you