Caffeine and cannabis are both psychoactive substances. But what are the effects of each in the brain and body?
Caffeine interacts primarily with adenosine receptors (ARs) in the brain, "It elicits its stimulating effects primary by virtue of its interactions with the AR: A1 and A2A receptors have been implicated to play more important roles. It only binds to the A2B at high doses, and the A3 receptor is insensitive to caffeine. By this mechanism, it primarily alters neural activities to influence mental activities and performance, resulting in increased mental alertness and wakefulness," explains Owolabi et al who published a study on the effects of caffeine and cannabis in the brain tissue of juvenile rats. Side effects of high doses of caffeine consist of diarrhea, dizziness, blurred vision, fast heartbeat, nausea, stomach ache, vomiting, anxious feeling, shakiness, and irritability. Many of these side effects are experienced in caffeine withdrawal. Caffeine in very high doses (between 3,200 milligrams and 10,000 milligrams at one time) can even lead to death.
Cannabis's main active agent is THC (tetrahydrocannabinol). The mechanism of action of THC includes interactions with the cannabinoid receptors CB1 and CB2. "Cannabis would influence brain activities in many brain regions because of the wide distribution of the cannabinoid receptors that THC can bind with; it binds in a similar way as anandamide which produces pleasurable feeling but, in addition to this, it alters other natural functions of these specific brain regions," explains Owolabi et al. The side effects from the overuse of cannabis consist of cognitive impairment, anxiety, dysphoria, panic, and paranoia. While there have been no reported cases of marijuana overdoses it can have some terrible side effects for the user. There have been some reported cases of consumers experiencing withdrawal symptoms from cannabis use including sleep disturbances, irritability, and anxiety.
In the category of impairment, cannabis can be seen as riskier than caffeine. Cannabis can have a large impact on cognitive abilities, memory, and motor skills. Caffeine does not have such a large impact in those areas and has even been found to help improve memory. According to Marilyn Cornelis, assistant professor of preventative medicine at Northwestern University's Feinberg School of Medicine, "Coffee suppresses the endocannabinoid chemicals that smoking marijuana boosts. That would suggest that coffee might generate the opposite effects as cannabis on the endocannabinoid system."
The study performed by Owolabi et al on the effects of caffeine and cannabis in the brain tissue of juvenile rats was found to have an increase in stimulatory effects from the caffeine and an increase in metabolic activity from the cannabis. The combined effects of cannabis and caffeine increased the enzyme levels, "This increase in activity would induce an increase in the utility of ATP and hydrolysis of glucose, thus the increase in G6PDH observed in this study. G6PDH plays crucial roles in energy metabolism and it is associated with the rate of cellular growth, development, and performance." The levels of G6PDH were increased in the brain tissue of all the animals treated in the study. Caffeine was found to produce more significant effects than cannabis.
While those who experience caffeine withdrawal can have more serious symptoms than those experiencing cannabis withdrawal, both drugs can put the body into stress from suddenly stopping or quitting. Unlike cannabis, caffeine can cause death in serious cases of high dosage intake at one time. However, cannabis can cause a larger impairment for the consumer than caffeine will cause. Caffeine and cannabis both influenced the activities of the enzymes and neurotransmitters in the brain, "Both stimulants altered brain chemistry relative to the tested enzymes and neurotransmitters."