How Does Cannabis Affect Your Emotions? What Weed Does to Mood, Memory and the Brain

Cannabis affects emotions mainly through THC, which acts on brain receptors that regulate reward, motivation and mood, so it can bring on relaxation and euphoria in the moment. But research on heavy users links regular, problematic use to weaker memory and planning, a blunted reward system and, in daily-smoking teens, a reduced ability to feel pleasure. Humans have been growing and using this plant for thousands of years, and only now is science catching up with how cannabinoids, the plant's active compounds, weave into our mental processes.

Here we unpack the relationship between cannabis and the human mind, the good and the bad. From how it shifts your mood to what weed does to your brain, especially memory and cognition, each section gets a little closer to explaining how this plant and its rich mix of cannabinoids can change the way we think, feel and see the world.

Along the way we'll look at recent research and at what people who've explored their minds with a joint in hand have reported. We'll also look at how cannabis, with its huge range of strains and terpene profiles, doesn't just alter states of consciousness but is also being studied, and used by patients, for a range of mental health conditions.

What does weed do to your brain? What science and psychology say

Human history has been tangled up with the cannabis sativa plant, better known as marijuana, for millennia. Over the centuries it's gone from just another crop to a cultural phenomenon, used both recreationally and medicinally all over the world.

Its recreational side has millions of people smoking or eating weed, and its growing acceptance as a medical tool in many countries shows just how many roles this plant plays today. But what does it actually do to our minds?

Recently, three major studies published in the Journal of Psychopharmacology, Neuropsychopharmacology and the International Journal of Neuropsychopharmacology shed new light on the complicated relationship between cannabis and cognition.

According to the United Nations Office on Drugs and Crime (UNODC), roughly 192 million people between 15 and 64 use cannabis recreationally worldwide, which shows how deeply rooted it is. Interestingly, around 35% of them are between 18 and 25, meaning a big chunk of users are young adults whose brains are still developing.

How THC affects your brain

THC (tetrahydrocannabinol), the main psychoactive player in cannabis, works through the brain's endocannabinoid system, home to receptors that respond to the plant's chemical compounds. These receptors are concentrated in the prefrontal and limbic areas, where they help run reward and motivation by regulating key neurotransmitters like dopamine, GABA (gamma-aminobutyric acid) and glutamate.

That chemistry has big implications. Dopamine, which drives motivation, reward and learning, is directly affected by THC. Glutamate and GABA, which are essential for cognitive processes like memory and learning, get pulled in too.

As we dig into the science and psychology, we get a clearer picture of how cannabis and its blend of cannabinoids shape our mental experience. From the endocannabinoid system to the fine print of neurotransmitter signaling, these are the pathways that connect weed and the mind.

Does weed affect memory and thinking? The cognitive effects of cannabis

The link between cannabis and cognition has been the subject of plenty of studies looking at how it can affect the mind, especially in people with cannabis use disorder. That's a condition marked by a persistent urge to use cannabis that gets in the way of daily life, and by some estimates it affects around 10% of users.

The research, which was covered by the BBC, looked at 39 people diagnosed with cannabis use disorder and compared them with a control group of 20 people who rarely or never use cannabis. Participants had to be sober on test day and took memory tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB), designed to measure how well the brain holds on to information.

What did the results show?

People with cannabis use disorder performed worse on the memory tests, pointing to a connection between long-term heavy use and memory problems. They also showed weaker “executive functions,” the mental processes behind things like flexible thinking, which suggests cannabis may affect a person's ability to handle complex mental tasks.

The age people started using turned out to matter a lot: those who started young showed a more pronounced decline in executive function.

And the cognitive effects weren't limited to heavy users. Even occasional users tended to make riskier decisions and had a harder time planning.

Does weed affect men and women differently?

Researchers also noticed differences between men and women. Men who use cannabis tended to have memory problems and trouble recognizing objects, while women had more trouble with attention and executive functions. Those differences held up even after accounting for factors like age, IQ, alcohol and nicotine use, mood, anxiety symptoms and other compulsive behaviors.

Put together, the findings paint a detailed picture of how cannabis can affect cognition, and they make a strong case for understanding the risks that come with heavy use.

How weed affects motivation and mental health

Beyond its obvious effects on cognition, recent research suggests cannabis also plays a role in motivation and mental health. Earlier studies had already pointed to a complicated interaction between cannabis and the brain processes behind reward and motivation.

That earlier work suggested cannabis may affect the brain circuits involved in reward and motivation, which could have real consequences for school and work performance and for people's overall drive.

In the newer study, participants did a task while their brains were scanned: they looked at blue and orange squares, and the orange ones came with a cash reward depending on how they responded. That let researchers see how the brain reacts to rewards.

Focusing on the ventral striatum, a key region in the brain's reward system, they found subtle effects from cannabis. Worth noting: the participants were moderate users, which suggests the emotional effects of weed could be stronger in chronic users.

The bottom line

There's evidence that smoking weed every day may be linked to mental health problems. In particular, it's been associated with high levels of anhedonia in teens, a condition that means being unable to feel pleasure.

All of this shows why it matters to understand the complicated interplay between cannabis, motivation and mental health, and why it's worth being aware of the potential risks of heavy use for your drive and your mental well-being.