bioRxiv (Cold Spring Harbor Laboratory)
June 5, 2025
Ekaterina Shatalina, Natalie Ertl, Kat Petrilli et al.
1 citation
preprint
Inhaling cannabis with THC alone or THC plus CBD reduces resting-state functional connectivity in brain networks that are rich in CB1 and CB2 cannabinoid receptors. Co-administering CBD with THC produced more widespread reductions than THC alone, affecting regions involved in cognition and emotion such as the prefrontal cortex, cingulate cortex, insula, hippocampus, amygdala, and putamen. Higher THC levels in the blood were linked to greater connectivity decreases when CBD was also present. Subjective drug effects correlated with connectivity changes in a region-specific way. The findings suggest that CBD may enhance rather than dampen THC's effects on brain connectivity, contrary to some earlier expectations.
The International Journal of Neuropsychopharmacology
February 1, 2025
Martine Skumlien, Tom P. Freeman, Daniel L. Hall et al.
In weekly cannabis users, cannabis suppresses the brain's anticipatory reward response to money, and cannabidiol (CBD) does not moderate this effect. The adolescent reward circuitry is not differentially sensitive to the acute effects of cannabis on reward anticipation. This double-blind, placebo-controlled, crossover study with 23 adults (26-29 years) and 24 adolescents (16-17 years) used functional magnetic resonance imaging (fMRI) to measure brain activity during a monetary reward anticipation task after inhaling cannabis with tetrahydrocannabinol (THC), THC plus CBD, or placebo. THC acutely reduced reward anticipation activity in the ventral striatum and right insula compared with placebo. THC plus CBD also reduced activity in these regions. The effects were the same in adolescents and adults.
Neuroscience and Biobehavioral Reviews
September 1, 2026
Isabella Goodwin, Dominic Oliver, Edward Chesney et al.
A meta-analysis of 41 double-blind, placebo-controlled experiments involving 1,020 infrequent cannabis users found that acute THC administration increases feelings of high, anxiety, and tiredness, while decreasing alertness and contentedness, with no effect on calmness. Inhaled THC dose-dependently increased high and contentedness but decreased calmness, with greater consistency in high and contentedness at higher doses. On a 100-point scale, inhaling 5 mg THC increased high by 34.3 points, anxiety by 14.4, tiredness by 26.3, and calmness by 4.5, while decreasing alertness by 40.2 and contentedness by 71.0. Oral THC showed no significant subjective effects, though higher oral doses produced more consistent alertness. These findings can inform public health guidance on expected THC effects.
Psychological Medicine
May 4, 2023
G. Trotta, Victoria Rodriguez, D. Quattrone et al.
Childhood adversity and cannabis use are both known risk factors for psychosis. This study examined whether cannabis use might explain the link between childhood adversity and psychotic disorders. Data from 881 first-episode psychosis patients and 1231 controls from the EU-GEI study showed that household discord was associated with psychosis partly through cannabis use. Lifetime cannabis use mediated 17% of the association, cannabis potency mediated 14%, and frequency of use mediated 29%. Similar results appeared for early exposure to household discord. The findings suggest that harmful cannabis use patterns partially explain how household discord leads to psychosis, and children exposed to challenging home environments could benefit from interventions to prevent cannabis misuse.