Cannabinoid combination affects cannabis-linked psychological symptoms

MedWire News: People who smoke different strains of cannabis appear to have different psychological symptoms, depending on the cannabinoid combination contained within a particular strain, UK study findings suggest.

Two of the various cannabinoids contained in cannabis - delta 9-tetrahydrocannabinol (THC) and cannabidiol (CBD) - have almost opposing action, as THC is psychomimetic and CBD is anxiolytic and possesses antipsychotic properties.

To examine the ink between proneness to psychosis and the presence of delusions and the ratio of CBD to THC, Celia Morgan and H Valerie Curran, from University College London, studied 140 individuals from an ongoing longitudinal drug study.

Hair samples were analyzed using gas chromatography/mass spectrometry for the presence of cannabinoids, allowing the identification of 20 individuals with only THC in their hair, 27 with THC+CBD, and 85 with no cannabinoids. The eight individuals who screened positive for CBD only in their hair were excluded due to the small number.

In order to assess psychosis proneness, the team administered the short form of the Oxford Liverpool Inventory of Life Experiences (OLIFE) questionnaire, while Peter's Delusion Inventory (PDI) was used to examine delusional thinking.

There were no significant differences between the THC and THC+CBD groups in terms of THC levels, and no differences between the three groups in terms of age or drug use other than cannabis. There were no significant differences in the subjective estimates of cannabis use between the THC and THC+CBD groups, aside from the number of days taken to smoke 3.5 g, at 10.2 days versus 5.0 days.

Individuals in the THC group had significantly higher scores on the OLIFE factor of unusual experiences, a marker for positive schizophrenia-like symptoms, than both the THC+CBD and controls groups, while THC+CBD individuals had significantly lower introvertive anhedonia scores than both controls and THC individuals.

Furthermore, THC individuals had significantly higher scores than controls on the PDI, at averages of 8.15 versus 5.48, with THC+CBD patients showing only a trend for greater scores, at an average of 7.22.

The team writes in the British Journal of Psychiatry: "This study is the first to demonstrate that hair analytic techniques can be used to define subsets of cannabis users. The implications of these findings are that people who smoke different strains of cannabis manifest different psychological symptoms."

They add: "Moreover, this suggests that smoking strains of cannabis containing CBD in addition to THC may be protective against the psychotic-like symptoms induced by THC alone."