Cannabis and Caffeine: An Interesting Relationship

Many people enjoy a cup of coffee with a joint, or a shot of espresso after a bong hit. But why is that? What is the relationship between coffee and cannabis that draws the two together? Thanks to Amsterdam, “coffee shop” is a euphemism for cannabis stores in Europe. This speaks to the enduring relationship between cannabis and caffeine. Indeed, as long ago as 1857, Dr. John Bell noted the ability of coffee to enhance the effect of cannabis. Over the past ten years, scientists have investigated the link between cannabis and caffeine and the short summary is – it’s complicated. However, we’ve done our best to boil it down for you. Read on to learn about the current state of the research into this iconic duo and why caffeine and cannabis combine so well.

Caffeine exerts its effect by working as an antagonist of adenosine receptors. Adenosine is an inhibitory neurotransmitter, meaning that it can inhibit the release of other neurotransmitters and decrease the activity of corresponding brain cells.

When a person is awake and alert, the levels of adenosine in our central nervous system are low. However, over time the levels increase, contributing to a feeling of drowsiness by inhibiting the release of neurotransmitters like dopamine and norepinephrine. By blocking the effects of adenosine, caffeine boosts the release of dopamine and norepinephrine, which explains the stimulating effects of caffeine.

Acute consumption of THC is also known to increase dopamine release (while long-term consumption may actually “blunt” the dopamine system). Dopamine is a neurotransmitter that is involved in the brain’s reward system.

So, it could be that consuming caffeine alongside cannabis increases the effect of each substance on the brain’s reward system. This could offer a partial explanation for the enduring popularity of the combination.

A 2009 Italian study found that mice exposed to caffeine long-term “sensitized GABAergic synapses to the presynaptic effect of cannabinoid CB1 receptor stimulation.” In plain English, long-term use of caffeine made some regions of the mice’s nervous systems more sensitive to cannabinoids like THC. 

Cannabis and caffeine have had an interesting relationship for over a hundred years.

The effects weren’t permanent, so after caffeine was removed from the mice’s drinking water, their response to cannabinoids slowly returned to normal. Dr. Rossi and his team concluded that the endocannabinoid system may play a role in caffeine’s psychoactive effects and caffeine’s ability to help with stress.

In 2012, the National Institute of Drug Abuse in Baltimore investigated the combined effect of THC and caffeine on working memory. THC is known to produce short-term memory deficits, while caffeine is known to alleviate some memory deficits. So, it’s reasonable to assume that caffeine could help to alleviate THC-induced memory deficits. However, that’s not what the results showed. In fact, when even a low dose of THC was combined with caffeine, memory performance in the rats was “significantly impaired.” The authors suggested that the results may be related to the effects of caffeine on cannabinoid signaling in the hippocampus, which is the area of the brain involved in the formation of new memories.

A human trial from 2018 used advanced metabolic profiling techniques to investigate the effect of coffee on human metabolism. The scientists discovered that long-term consumption of 4-8 cups of coffee affected human metabolism in dozens of ways. One of the most interesting effects noted in the study was on the endocannabinoid system.

This could indicate a reduction in levels of endocannabinoids in the bodies of coffee drinkers. Another factor which is known to decrease the levels of endocannabinoids in our bodies: stress. Taking this into account, the researchers suggested that chronic consumption of coffee may cause a similar decrease by exposing our bodies to prolonged, low-level stress. What this means for the effects of cannabis and caffeine still isn’t clear; human metabolism is as esoteric as it is misunderstood.

Furthermore, the researchers couldn’t be certain that caffeine was behind the studied effects on human metabolism. Like cannabis, coffee contains a number of active constituents. Could it be that by reducing the levels of endocannabinoids in our body, caffeine makes the cannabinoids from cannabis more enjoyable or attractive? Subjectively, consumers might say yes, but the research remains opaque.

The subjective evidence available so far seems to support the idea of a synergistic effect between caffeine and cannabis. To date, this relationship is not fully understood though, and researchers are still investigating the precise effects of the combination.

Amsterdam is renowned for its “coffee shops”, with more than a hundred of them dotted around the city. photo credit

However, it’s clear that consuming cannabis and caffeine together causes a different reaction than consuming either one alone. Both cannabis and caffeine have varying effects depending on dosage and short-term vs. long-term use. So, exactly how the combination affects us – and whether that’s helpful or not – will depend on a lot of factors.

Some consumers find that cannabis and caffeine is a bit too much, leaving them jittery and anxious. For others, mixing the two makes for a magical combination which boosts focus, energy, creativity, and motivation. The enduring popularity of the pair is evidence enough that plenty of cannabis consumers continue to find value in the combination.

Do you enjoy combining cannabis and coffee? Why or why not? Share your thoughts and experiences in the comments below.

Photo Credit: Jessica Lewis (license)