Trajectory of Adolescent Cannabis Use on Addiction Vulnerability.

James J. Peters Veterans Administration, Bronx, NY, USA. Electronic address: .
Neuropharmacology (Impact Factor: 5.11). 08/2013; 76. DOI: 10.1016/j.neuropharm.2013.07.028
Source: PubMed


The adolescent brain is a period of dynamic development making it vulnerable to environmental factors such as drug exposure. Of the illicit drugs, cannabis is most used by teenagers since it is perceived by many to be of little harm. This perception has led to a growing number of states approving its legalization and increased accessibility. Most of the debates and ensuing policies regarding cannabis were done without consideration of its impact on one of the most vulnerable population, namely teens, or without consideration of scientific data. We provide an overview of the endocannabinoid system in relation to adolescent cannabis exposure and provide insights regarding factors such as genetics and behavioral traits that confer risk for subsequent addiction. While it is clear that more systematic scientific studies are needed to understand the long-term impact of adolescent cannabis exposure on brain and behavior, the current evidence suggests that it has a far-reaching influence on adult addictive behaviors particularly for certain subsets of vulnerable individuals.

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    • "In the long run, this substance can induce many behavioral (e.g., risktaking behaviors or motivational impairments), physiological (e.g., respiratory or neurocognitive symptoms), psychological (e.g., anxiety or mood disorders) and social (e.g., work, school or interpersonal disabilities) effects on adolescents and young adults (Patton et al., 2002; Looby and Earleywine, 2007; Zvolensky et al., 2010; Degenhardt et al., 2012; Thames et al., 2014). Moreover, cannabis use in adolescence may increase the risk of addictive behaviors in adulthood, particularly for vulnerable individuals (Hurd et al., 2013). Adolescence thus constitutes a key period for investigating cannabis use and particularly to explore the early consumption stages. "
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    ABSTRACT: Cannabis is one of the most commonly drugs used by teenagers. Expectancies about its effects play a crucial role in cannabis consumption. Various tools have been used to assess expectancies, mainly self-report questionnaires measuring explicit expectancies, but implicit measures based on experimental tasks have also been developed, measuring implicit expectancies. The aim of this study was to simultaneously assess implicit/explicit expectancies related to cannabis among adolescent users and non-users. 130 teenagers attending school (55 girls) were enrolled (Age: M=16.40 years); 43.84% had never used cannabis ("non-users") and 56.16% had used cannabis ("users"). They completed self-report questionnaires evaluating cannabis use, cannabis-related problems, effect expectancies (explicit expectancies), alcohol use, social and trait anxiety, depression, as well as three Implicit Association Tests (IAT) assessing implicit expectancies. Adolescents manifested more implicit affective associations (relaxation, excitation, negative) than neutral ones regarding cannabis. These were not related to explicit expectancies. Cannabis users reported more implicit relaxation expectancies and less negative explicit expectancies than non-users. The frequency of use and related problems were positively associated with the explicit expectancies regarding relaxation and enhancement, and were negatively associated with negative explicit expectancies and negative implicit expectancies. Findings indicate that implicit and explicit expectancies play different roles in cannabis use by adolescents. The implications for experimentation and prevention are discussed.
    No preview · Article · Nov 2015
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    • "The adolescent brain is particularly sensitive to perturbations, and consequently exposure to cannabis might affect development of the endocannabinoid system and induce neurobiological changes that affect adult brain function. These long-lasting changes might contribute to negative outcomes such as problematic patterns of use of cannabis and other illicit drugs (Copeland and Swift, 2009; Chadwick et al, 2013; Hurd et al, 2014). "
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    ABSTRACT: Cannabis is the most commonly used illicit drug worldwide, and use is typically initiated during adolescence. The endocannabinoid system plays an important role in formation of the nervous system, from very early development through adolescence. Cannabis exposure during this vulnerable period might lead to neurobiological changes that affect adult brain functions and increase the risk of cannabis use disorder. The aim of this study was to investigate whether exposure to Δ(9)-tetrahydrocannabinol (THC) in adolescent rats might enhance reinforcing effects of cannabinoids in adulthood. Male adolescent rats were treated with increasing doses of THC (or its vehicle) twice/day for 11 consecutive days (PND 45-55). When the animals reached adulthood, they were tested by allowing them to intravenously self-administer the cannabinoid CB1-receptor agonist WIN55,212-2. In a separate set of animals given the same THC (or vehicle) treatment regimen, electrophysiological and neurochemical experiments were performed to assess possible modifications of the mesolimbic dopaminergic system, which is critically involved in cannabinoid-induced reward. Behavioral data showed that acquisition of WIN55,212-2 self-administration was enhanced in THC-exposed rats relative to vehicle-exposed controls. Neurophysiological data showed that THC-exposed rats displayed a reduced capacity for WIN55,212-2 to stimulate firing of dopamine neurons in the ventral tegmental area and to increase dopamine levels in the nucleus accumbens shell. These findings-that early, passive exposure to THC can produce lasting alterations of the reward system of the brain and subsequently increase cannabinoid self-administration in adulthood-suggest a mechanism by which adolescent cannabis exposure could increase the risk of subsequent cannabis dependence in humans.Neuropsychopharmacology accepted article preview online, 21 September 2015. doi:10.1038/npp.2015.295.
    Full-text · Article · Sep 2015 · Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology
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    • "For this reason, the animal studies addressing this issue are crucial research contributions into the long-lasting consequences of cannabinoid exposure during adolescence. As for prenatal intake, there are also excellent reviews on cannabinoid exposure during adolescence and the ensuing adult behavioral alterations (Chadwick et al., 2013; Hurd et al., 2014; Realini et al., 2009; Renard et al., 2014; Rubino and Parolaro, 2008; Schneider, 2009, 2008; Trezza et al., 2012; Viveros et al., 2011a,b), leading us to focus mainly on the most consistent or interesting findings. We will first review the studies on long-term cognitive alterations induced by adolescent cannabinoid exposure (see Table 5), before focusing on the emotional changes (including anxiety or depressive-like behavior: Table 6), thereafter assessing the data available on the altered sensitivity to drugs of abuse found in cannabinoid-exposed individuals. "

    Full-text · Dataset · May 2015
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