Effect of high-potency cannabis on corpus callosum microstructure

Abstract

BackgroundThe use of cannabis with higher Δ9-tetrahydrocannabinol content has been associated with greater risk, and earlier onset, of psychosis. However, the effect of cannabis potency on brain morphology has never been explored. Here, we investigated whether cannabis potency and pattern of use are associated with changes in corpus callosum (CC) microstructural organization, in patients with first-episode psychosis (FEP) and individuals without psychosis, cannabis users and non-users.MethodThe CC of 56 FEP (37 cannabis users) and 43 individuals without psychosis (22 cannabis users) was virtually dissected and segmented using diffusion tensor imaging tractography. The diffusion index of fractional anisotropy, mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity was calculated for each segment.ResultsAcross the whole sample, users of high-potency cannabis had higher total CC MD and higher total CC AD than both low-potency users and those who never used (p = 0.005 and p = 0.004, respectively). Daily users also had higher total CC MD and higher total CC AD than both occasional users and those who never used (p = 0.001 and p < 0.001, respectively). However, there was no effect of group (patient/individuals without psychosis) or group x potency interaction for either potency or frequency of use. The within-group analysis showed in fact that the effects of potency and frequency were similar in FEP users and in users without psychosis.ConclusionsFrequent use of high-potency cannabis is associated with disturbed callosal microstructural organization in individuals with and without psychosis. Since high-potency preparations are now replacing traditional herbal drugs in many European countries, raising awareness about the risks of high-potency cannabis is crucial.

Cannabis use in early psychosis is associated with reduced glutamate levels in the prefrontal cortex

“…Moreover, the cross-sectional design, does not allow for a strong cause-effect interpretation of the findings. Furthermore, although other studies that have used self-report measures have also shown an association with brain structural alterations (Rigucci et al 2016), the lack of objective measures of cannabis use in our study is an important limitation. However, there is published evidence indicating that asking patients with psychosis about their use of cannabis is, at least in some situations, more accurate than, or as reliable as, urine or blood testing which can only provide information on recent use (Freeman et al 2014).…”

Can we make cannabis safer?

“…Some neuroimaging studies have also suggested that the MRI correlates of cannabis use may vary with exposure to CBD. One study found that regular use of high-potency cannabis was associated with alterations in the corpus callosum, an effect that was absent in hash users 39 . Two other MRI studies have reported that cannabis users had smaller hippocampal volumes than non-users, but that this was not evident in cannabis users with hair samples that were positive for CBD 40,41 .…”

“…Alternative approaches include taxation based on THC content, although further research is needed their impact (including use of more harmful, synthetic cannabinoids). Only very recently have studies differentiated between different types of cannabis based on THC content 30,[37][38][39] , and most of these studies do not involve measures of THC and CBD content, but proxy measures of potency, such as analysis of police seizures or coffee shop cannabis, and a reliance on self-report measures. Although self-report measures are associated with THC and CBD content, these associations are modest and are weaker among infrequent users 84,85 .…”

Marijuana’s Role in The Adolescent Population

“…Another significant factor in the reduction of cognitive processing are the cannabinoid receptors that are primarily located on neurons but also found on myelinating glial cells [49].…”