Acceptance of pharmaceutical cannabis substitution by cannabis using patients with schizophrenia
Jan van Amsterdam, Jojanneke Vervloet, Gerdien de Weert, Victor J. A. Buwalda, Anna E. Goudriaan and Wim van den Brink
Harm Reduction Journal, 2018, 15, 47, 1-4.
Doi : 10.1186/s12954-018-0253-7
Background : Cannabis-smoking patients with a psychotic disorder have poorer disease outcomes than non-cannabis-smoking patients with poorest outcomes in patients smoking high-potency cannabis (HPC) containing high Δ9-tetrahydrocannabinol (THC) and low cannabidiol (CBD). Quitting cannabis smoking or substitution of HPC by cannabis variants containing less THC and/or more CBD may benefit these patients. The present study explores whether daily HPC-smoking patients with schizophrenia accept smoking such variants.
Methods : Twelve male patients were asked to smoke on six different occasions one joint: on two occasions, the cannabis they routinely smoke (HPC; not blind), and blind in random order; on two occasions, cannabis containing low THC and no CBD; and on two occasions, cannabis containing low THC and high CBD.
Results : Both substitute variants were appreciated, but patients preferred the HPC they usually smoked. The effect of the low THC/high CBD variant was reported by 32% to be too short and by 36% to be not strong enough, whereas this was reported by 5% and 64%, respectively, for the low THC cannabis variant.
Conclusions : Based on these findings, a larger and longer study on the efficacy of cannabis substitution treatment in HPC-smoking patients with schizophrenia seems feasible and should be considered.
Trial registration : 2014-005540-17NL. Registered 22 October 2014, 2014-005540-17NL 20141215 CTA.xml
Keywords : Schizophrenia, Psychosis, Cannabis, Skunk, CBD, High-potency cannabis
Prevalence of cannabis use in patients with a psychotic disorder is high [1, 2]. According to patients, cannabis is often used as self-medication to ameliorate positive and/or negative symptoms , to get “high,” and/or for pleasure and social motives [4–6]. However, there is growing evidence that (a) patients with a psychotic disorder who smoke high-potency cannabis (HPC), i.e., cannabis containing high concentrations of Δ9-tetrahydrocannabinol (THC) and low concentrations of cannabidiol (CBD), have poorer disease outcomes than either non-cannabis-smoking patients or patients that discontinue their cannabis use and (b) patients who continue the use of HPC show more psychotic episodes and an increased probability of (re)hospitalization [7, 8].
THC seems to be the main driver of the psychotogenic effects of cannabis, whereas CBD may inhibit THC induced anxiety and psychosis. In a large web-based cross-sectional survey, it was shown that persons who smoked cannabis with a low THC/CBD ratio had significantly fewer psychotic-like experiences than those smoking cannabis with higher THC/CBD ratios . Furthermore, co-administration of CBD and THC induced less anxiety and fewer psychotic-like symptoms than THC alone [10–14], implicating that smoking CBD-enriched cannabis (and containing less THC) may be less harmful for patients with a psychotic disorder who do not want or cannot quit smoking cannabis [13, 14]. Therefore, prescribing cannabis containing less THC and/or more CBD as a substitution for HPC is a promising form of harm reduction, i.e., allowing the use of cannabis and simultaneously reducing the risk of psychotic episodes and (re)hospitalization. In the current study, we investigated whether patients with a psychotic disorder
using HPC accept smoking less harmful cannabis variants, i.e., cannabis variants with less THC and/or more CBD.