The Cannabis Pathway to Non-Affective Psychosis may Reflect Less Neurobiological Vulnerability

Løberg, Else‐Marie; Helle, Siri; Nygård, Merethe; Berle, Jan Øystein; Kroken, Rune A.; Johnsen, Erik

doi:10.3389/fpsyt.2014.00159

Cited by 26 publications

(26 citation statements)

References 207 publications

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“…Cross-sectional and longitudinal studies show a consistent relationship between cannabis use and psychotic disorders (previously reviewed[13, 77, 78]). Several studies show that cannabis use occurs prior to onset of psychosis [79–81] and is associated with earlier onset of illness[82–86].…”

Section: Methodsmentioning

confidence: 96%

Cannabis and development of dual diagnoses: A literature review

Hanna

Perez

Ghose

2016

The American Journal of Drug and Alcohol Abuse

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Background The use of cannabis has garnered more attention recently with ongoing efforts at marijuana legalization. The consequences of cannabis use are not clearly understood and remain a concern. Objectives to review the acute and persistent effects of cannabis use and associations with psychiatric disorders Methods Using Pubmed and PsychInfo, we conducted a narrative review of the literature on cannabis and psychiatric comorbidity using the keywords cannab*, marijuana, schizo*, psychosis, mood, depression, mania, bipolar and anxiety. Results There is substantial evidence of cannabis use leading to other illicit drug use and of an association between cannabis use and psychosis. A few reports suggest an association with bipolar disorder while the association with depression and anxiety disorders is mixed. Conclusions Whenever an association is observed between cannabis use and psychiatric disorders, the relationship is generally an adverse one. Age at the time of cannabis use appears to be an important factor with stronger associations observed between adolescent onset cannabis use and later onset of psychiatric disorders. Additional studies taking into account potential con-founds (such as withdrawal symptoms, periods of abstinence and other substance use) and moderators (such as age of initiation of cannabis use, amount and frequency of drug use, prior history of childhood maltreatment and gender) are needed to better under-stand the psychiatric consequences of cannabis use.

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Section: Methodsmentioning

confidence: 96%

Cannabis and development of dual diagnoses: A literature review

Hanna

Perez

Ghose

2016

The American Journal of Drug and Alcohol Abuse

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“…Cannabis‐using psychotic patients also tend to have higher IQ and better neurocognition than non‐using psychotic patients. They also have higher premorbid IQ and better premorbid social function and are less likely to show neurological soft signs.…”

Section: Psychosismentioning

confidence: 99%

Traditional marijuana, high‐potency cannabis and synthetic cannabinoids: increasing risk for psychosis

et al. 2016

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Epidemiological evidence demonstrates that cannabis use is associated with an increased risk of psychotic outcomes, and confirms a doseresponse relationship between the level of use and the risk of later psychosis. High-potency cannabis and synthetic cannabinoids carry the greatest risk. Experimental administration of tetrahydrocannabinol, the active ingredient of cannabis, induces transient psychosis in normal subjects, but this effect can be ameliorated by co-administration of cannabidiol. This latter is a constituent of traditional hashish, but is largely absent from modern high-potency forms of cannabis. Argument continues over the extent to which genetic predisposition is correlated to, or interacts with, cannabis use, and what proportion of psychosis could be prevented by minimizing heavy use. As yet, there is not convincing evidence that cannabis use increases risk of other psychiatric disorders, but there are no such doubts concerning its detrimental effect on cognitive function. All of the negative aspects are magnified if use starts in early adolescence. Irrespective of whether use of cannabis is decriminalized or legalized, the evidence that it is a component cause of psychosis is now sufficient for public health messages outlining the risk, especially of regular use of high-potency cannabis and synthetic cannabinoids.Key words: Cannabis, psychosis, marijuana, synthetic cannabinoids, cognitive function, brain structure, genetic predisposition, early adolescence (World Psychiatry 2016;15:195-204) The use of cannabis has been illegal in most countries since the 1930s, but this has not deterred use 1 . Currently, cannabis is used by around 180 million people globally 2 . The tensions produced by this unsatisfactory situation have resulted in much attention being paid to the legal status of cannabis.Possession of the drug in small quantities has been decriminalized officially in countries such as Portugal and the Netherlands, and unofficially in many more. In 2013, Uruguay became the first nation to legalize the sale, cultivation and distribution of cannabis 3 . Four US states have also legalized recreational use, and another twenty-five US states as well as Canada permit so-called "medicinal marijuana". While Uruguay has strict rules concerning access, laws vary state by state in the US, with policy being increasingly driven by entrepreneurs in search of profit, and law makers in search of taxes.Given the above, it seems likely that consumption of cannabis will increase rather than decrease. This makes it imperative to understand the possible adverse consequences of use, even if they only affect a minority of users. In this paper we start by reviewing cannabinoids and the endocannabinoid system. We then focus on cannabis use and risk of psychiatric disorder, particularly psychosis, before touching on the effects on cognition and brain structure. CANNABINOIDS AND THE ENDOCANNABINOID SYSTEMCannabis contains over one hundred cannabinoids 4 , the most important of which are tetrahydrocannabinol (THC) and ...

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“…Substance abuse also seems to lead to earlier onset of schizophrenia [45,47]. However, determining causality between two conditions based on which was observed first may be misleading.…”

Section: Causalitymentioning

confidence: 99%

Understanding the Relationship Between Amphetamines and Psychosis

Rognli

Bramness

2015

Curr Addict Rep

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Use of amphetamine and methamphetamine (hereafter amphetamines) can cause acute psychotic symptoms and may also contribute to persistent psychotic conditions such as schizophrenia. Still, much remains uncertain about the mechanisms and nature of this relationship. In this paper, we review certain aspects of this relationship, with particular emphasis on papers published during the past 3 years. A review of the literature reveals that, in addition to the established knowledge that amphetamines can cause acute psychotic symptoms, more evidence has emerged that amphetamines may play a role also in the pathogenesis of schizophrenia. Determining causality for the amphetamine-psychosis association has, however, proven complicated. Reversed causality may be the case, as may be the notion that both use of amphetamines and psychosis reciprocally affect each other with deteriorating effects on both conditions. Clinical features like sensitization to amphetamines precipitating psychosis, that even amphetamineinduced psychosis may persist, and diagnostic transition from amphetamine-induced to primary psychosis suggest a continuous and mutual interaction between individual vulnerability, amphetamine exposure, and psychosis. The high transition rates also point to amphetamine-induced psychosis as a major risk factor for primary psychosis. Mortality rates are high for both psychosis and use of amphetamines, and we lack highquality treatment guidelines to apply when these two conditions occur together. Amphetamine-induced psychosis may be more affiliated with primary psychosis than previously assumed. Some clinical implications are suggested.

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The Cannabis Pathway to Non-Affective Psychosis may Reflect Less Neurobiological Vulnerability

Cited by 26 publications

References 207 publications

Cannabis and development of dual diagnoses: A literature review

Cannabis and development of dual diagnoses: A literature review

Traditional marijuana, high‐potency cannabis and synthetic cannabinoids: increasing risk for psychosis

Understanding the Relationship Between Amphetamines and Psychosis

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