Cannabinoids increase tonic and phasic dopamine release. Do you know what else gives rise to feelings of happiness? Cannabis. This herb can quickly catapult us to a positive state. This effect is due to THC, which, according to studies, causes a short-term increase in dopamine levels in the brain.
In fact, research on cannabis over the years has established a connection between smoking or ingesting cannabis and an increase in dopamine concentration. The THC high comes from a chemical substance called dopamine. The brain releases dopamine to reward us for behavior that, historically, has improved our chances of survival. Short-term marijuana use is known to increase dopamine in the brain indirectly.
While the cannabinoids contained in marijuana do not act directly on dopamine neurons, they do act on the body's endocannabinoid system (ECS), which temporarily suppresses GABA inhibitors. GABA neurons are neurons that inhibit dopamine production; when suppressed, dopamine production increases. Given the widespread use of cannabinoids and the relationship between exposure to THC and adverse outcomes, it is imperative to understand the neurobiological effects of THC. In addition to this complex picture, there are several diseases that are related to deficiencies or alterations in both the endocannabinoid and dopamine systems.
Similarly, the THC content of cannabis has increased significantly since the first clinical studies102, since doses of THC can exceed 40 mg per joint (joint, cannabis cigarette), 103, so the doses used in published imaging studies no longer reflect typical exposure to THC in cannabis consumers. Lately, the THC content of cannabis has been increasing12, and synthetic analogs of THC (potent cannabinoid agonists, called “spices”) are now widely used13. However, some researchers have also studied the use of cannabinoids as a way to treat addiction to more dangerous substances, such as opioids. While these processes are natural parts of human functioning, phytocannabinoids can bind to these same endocannabinoid receptors, triggering some of the same effects as endocannabinoids. French also conducted a similar study with CBD instead of THC and found that there was no evidence that cannabidiol increased dopamine in reward pathways.
Cannabis may have biphasic effects on dopamine, meaning that small doses may increase dopamine, but higher doses may, in fact, lower it. Research on cannabis for these conditions has yielded mixed results, as cannabis increases and decreases symptoms depending on how it is consumed. In a study on the self-administration of CB1R agonists in rats96, exposure to THC during adolescence increased the reinforcing effects of cannabinoids in adulthood, suggesting that exposure to THC during adolescence increased the potential for addiction during a critical period of development. They discovered that the cannabinoid acts as a partial agonist at the dopamine D2 receptor, meaning that it directly interacts with the brain's reward system.
When these systems are deficient, cannabinoids can help change things in the right direction. So, you know that THC affects the dopamine system by mimicking our endocannabinoids, but it's not the only cannabinoid that causes changes in the reward system. THC mimics anandamide, a natural cannabinoid that the body produces to work on the endocannabinoid system, where it plays a role in energy, appetite, mood and perception of time by regulating GABA. The evidence that gestational exposure to THC is associated with deregulated dopamine synthesis in old age has important potential implications for public health, given the prevalence of cannabis use among women of childbearing age and that the liberalization of cannabis laws worldwide may be associated with Increased use of the drug among pregnant and nursing mothers.