How cannabis–and different types of cannabis–can affect mental health has been the subject of much misinformation, research, interpretation, and debate. As scientists get a closer look at how their subjects are affected by cannabis in the context of mental health, we can begin to grasp the potential for how it might best be used medicinally for the mind.

Stress Can Lead to Mental Health Disorders

Our stress response plays a big part in our mental health as humans. When a person responds to a stressful situation, their eyes and ears send information to the amygdala, an area of the brain that manages emotional processing. Upon the amygdala perceiving danger, it sends a distress signal to the hypothalamus. This triggers the pituitary gland, a rush of hormones sent to the adrenal glands. This is what some call “fight or flight”. It’s a response that activates the sympathetic nervous system, inhibits the parasympathetic nervous system, and mobilizes the necessary energies to overcome these stressors.

Constant stress can have long term effects on both the mind and the body.  Damage to blood vessels and arteries, increased blood pressure, and an increased risk of heart attack or stroke are all ways that stress can negatively impact the way the body functions. 

Stress isn’t a medical diagnosis, so there’s no specific treatment for it. Those who struggle to manage stress in healthy ways may be suffering from a mental health condition such as PTSD, anxiety, or depression.

When diagnosing mental health conditions, doctors typically use a combination of therapy and medication. Many pharmaceutical drugs used to treat mental health disorders can come with side effects. In some patients, they don’t work at all or worsen the condition. This leaves many users searching for alternatives. 

How Could Cannabis Be Helpful in Treating Mental Health Disorders? 

According to a 2016 article in the journal Clinical Psychology Review, “cannabis is among the world’s most widely used psychoactive substances, and the associations between cannabis use, cognition, and mental health have been the subject of substantial research.” 

It’s long been known that people experiencing stress find cannabis attractive as a means to treat stress, much like alcohol and other pleasure-seeking behaviors. But a 2020 study attempts to explain why. In a model using mice, it was found that a break in an anxiety-producing connection between the amygdala and the frontal cortex was caused by 2-AG, a molecule produced by the brain that activates the same receptors as those found in cannabis. The 2-AG’s function is to help regulate the immune system function, a person’s appetite, and pain management. Out of all the cannabinoids, 2-AG is one of the most studied endogenous cannabinoids. 

“The circuit between the amygdala and the frontal cortex has been shown to be stronger in individuals with certain types of anxiety disorders. As people or animals are exposed to stress and get more anxious, these two brain areas glue together, and their activity grows stronger together,” said Sachin Patel, MD, PhD, the paper’s corresponding author.

“We might predict there’s a collapse in the endocannabinoid system, which includes 2-AG, in the patients that go on to develop a disorder. But, not everyone develops a psychiatric disorder after trauma exposure, so maybe the people who don’t develop a disorder are able to maintain that system in some way. Those are the things we’re interested in testing next,” Patel said. 

Treating PTSD with THC

Studies have revealed improvements among PTSD patients receiving cannabis doses with higher levels of THC. 

One 2020 study studied the amygdala responses in three groups of participants suffering from PTSD. The study showed that participants who took low doses of THC showed measurable signs of reduced fear and anxiety in situations designed to trigger fear. 

One placebo-controlled, double-blind study in 2021 conducted by the Multidisciplinary Association for Psychedelic Studies (MAPS) specified levels of improvement among participants using smoked cannabis blends with a 9 percent THC concentration. The research showed improvements in samples containing 11 percent CBD, as well as mixed samples containing 8 percent of both THC and CBD. Over the course of a year, the study found that cannabis users reported a greater decrease in the severity of their PTSD symptoms. They also were more than 2.5 times as likely to no longer meet the diagnostic criteria for PTSD as those who did not use cannabis.

Using Cannabis with Mental Health in Mind

For some, CBD can lessen the unwanted psychoactive effects of THC such as hallucinations and paranoia. It can also reduce anxiety. The potential negative effects of THC can be lower if there is more CBD in the plant.

A 2018 study from Washington State University examined how patients who reported levels of stress, anxiety and depression were affected by smoking different strains and quantities of cannabis at home. The team found that one puff of medical marijuana high in CBD and low in THC reduced symptoms of depression, two puffs of any type of cannabis was sufficient to reduce symptoms of anxiety, and 10 or more puffs of cannabis high in CBD and high in THC produced the largest reductions in stress.

Can Cannabis Negatively Impact Mental Health? 

Some studies indicate that cannabis may make users more likely to develop temporary psychosis (not knowing what is real, hallucinations, and paranoia) or long-lasting mental disorders like schizophrenia. It’s been hypothesized that cannabis triggers the onset or relapse of schizophrenia in predisposed people. However, establishing direction of causality is difficult and is most appropriately assessed in non-clinical samples. Many users also take other prescriptions and illicit drugs in addition to cannabis which creates methodological problems and a lack of reliable evidence. More research into this topic is needed. 


Portions of this article were originally published on MedicateOH thanks Duber Medical for allowing us to republish this content to reach a wider audience.


  • Gabrielle Dion

    Medicate OH's Founder and Publisher is a native of Cincinnati, Ohio and holds an undergraduate degree in journalism and a master's degree in public administration, both from Northern Kentucky University. She has more than 20 years of experience writing and editing professionally for the medical and wellness industries, including positions with The Journal of Pediatrics, Livestrong, The Cincinnati Enquirer, and Patient Pop.