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

Abstract

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 ...

What causes psychosis? An umbrella review of risk and protective factors

“…A second limitation is that the umbrella review approach may favour the selection of more commonly and readily studied factors, since they are more likely to be included in a metaanalysis. We cannot exclude the possibility that some promising factors, despite having sufficient data, do not have a corresponding eligible meta-analysis, such as mood and anxiety disorders [143][144][145] , personality disorders 146 , attachment 147 , alcohol and psychoactive substances [148][149][150][151] , sleep dysfunction 152 , homelessness 153 or pervasive developmental disorders 154 . However, this possibility is becoming less likely in the current era, with meta-analyses being performed massively, to the point that for several topics multiple meta-analyses are available 155,156 .…”

Synthetic Cannabinoid Use in a Psychiatric Patient Population: A Pilot Study

“…Additionally, they have strong cannabimimetic effects, can induce euphoria and relaxation, and enable patients to feel calm and safe [10,11,16,17]. However, accumulating evidence indicates that SCs can induce serious side effects, including psychosis [9,18,19,20]. The association between NC use and the risk of psychosis is controversial; however, less is known about the potential of SCs to cause psychosis.…”

“…The association between NC use and the risk of psychosis is controversial; however, less is known about the potential of SCs to cause psychosis. SCs are believed to have a greater potential to induce psychosis than NC because they have higher affinity for cannabinoid receptor type 1 (CB1) [18,19,21,22]. Moreover, previous studies suggest that the side effects induced by SCs may be more severe and may occur more frequently than those induced by NC [22,23,24,25,26,27,28,29,30].…”

Dispensary cannabidiol marijuana and first-episode mania

“…1 These psychotomimetic properties are largely due to the effects of Δ-9-tetrahydrocannabinol, 1 of approximately 60 cannabinoids in marijuana. 2 Although evidence in bipolar disorder is less robust than in psychosis, there is an association between cannabis use in bipolar disorder and younger age of onset, poorer medication adherence, a more severe course of illness, a higher number of manic or depressive episodes and a greater degree of dys phor ia versus euphoria (for a review, see Aubry 3 ).…”