CBD has a suppressive effect on cytokine-induced degradation of tryptophan, allowing it to increase tryptophan levels in unstimulated brain areas and create a passive baseline increase.
Tryptophan
is a key compound in the serotonin synthesis pathway, and its increased bioavailability can cause an increase in serotonin levels. CBD also interacts with several receptors that are sensitive to many drugs and neurotransmitters, such as anandamide, dopamine, serotonin, GABA-A, and 5-HT1. Anandamide helps regulate other brain chemicals, such as dopamine and serotonin. By interacting with dopamine receptors, CBD helps to raise dopamine levels and regulate cognition, motivation, and reward seeking behaviors.Neuroimaging studies have demonstrated that CBD modulates brain activity and connectivity in neural systems relevant to psychosis and anxiety, possibly reflecting the therapeutic effects of CBD. CBD has been shown to have different effects on patients compared to THC. Five neuroimaging studies reported the acute effects of CBD on brain function in patients with a psychiatric disorder. In comparison to THC, CBD had a greater impact on functional connectivity between certain brain regions.
It also increased activation compared to placebo in the parahippocampus during auditory processing and reduced activation in this region during the processing of fearful faces. Nine double-blind, placebo-controlled studies investigated the acute effects of CBD on the brain function of healthy volunteers. Seven functional magnetic resonance imaging studies investigated the acute effects of CBD in direct comparison with those induced by THC, during a state of rest or during a cognitive task. A linear comparison between the three groups showed that patients being treated with CBD had intermediate activation in several groups located bilaterally in the inferior frontal gyrus and in the left middle frontal gyrus.
