Cannabis and mental health: Understanding the connection

Cannabis, also commonly referred to as weed, marijuana, ganja, or pot, is a psychoactive substance derived from the Cannabis sativa plant. It has wide-ranging effects on both the body and mind.

This dispenseroO blog explores the intricate relationship between cannabis and mental health, while also touching on its physical effects.

Table of Contents

• How Cannabis Interacts with the Brain
• Edible Cannabis: A Different Experience
• Short-Term and Long-Term Effects on the Brain
• Psychological Effects of Cannabis Use
• Is Cannabis Addictive?
• Can Cannabis Trigger Mental Health Problems?
• Physical Health Impacts of Cannabis Use
  • Cancer
  • Heart Health
  • Lung Function
• Quitting Cannabis: Support and Guidance
  • Tips & Tools for Quitting

 

How cannabis interacts with the brain

Cannabis contains almost 100 different cannabinoids. The two most well-known are tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the main psychoactive component, and in highly potent forms like ‘skunk’, its effects are significantly stronger due to elevated THC levels.

When inhaled, THC enters the bloodstream quickly and travels to the brain, where it binds to cannabinoid receptors. This interaction triggers the release of neurotransmitters, particularly dopamine, which is associated with pleasure, reward, and mood regulation. These neurochemical changes influence emotions, thoughts, and behaviour.

Edible cannabis: A different experience

Cannabis can also be consumed as an edible — such as in brownies, chocolates, or gummies. Unlike smoking, edibles must pass through the digestive system before entering the bloodstream, resulting in a delayed onset of effects.

However, once absorbed, the effects are typically more intense and longer-lasting. Because it’s harder to measure THC content in edibles, experts advise users to “start low and go slow” to avoid accidental overconsumption.

Short-term and long-term effects on the brain

The short-term cognitive effects of cannabis use—especially within 24 hours—include changes in concentration, memory, coordination, motor skills, and time perception.

Long-term impacts are especially concerning for developing brains, including foetuses, children, and teenagers. Research has linked prenatal cannabis exposure to difficulties in attention, memory, problem-solving, and behavioural regulation in children.

Related: So you want to know what Cannabis is?

Adolescents who use cannabis before the age of 18 risk disrupting brain development in areas related to learning and memory. These effects may be long-lasting, if not permanent.

Several factors influence how cannabis affects the brain:

• The THC concentration

• Frequency of use

• Age of first use

• Concurrent use of other substances (e.g. alcohol, tobacco, other drugs)

Psychological effects of cannabis use

While cannabis is now legal in various countries for medicinal or recreational use, it’s important not to assume that it’s completely safe. Its psychoactive effects can vary widely from person to person.

Some people may experience:

• A sense of calm or euphoria

• Increased sociability

• Laughter

• Enhanced sensory perception

However, cannabis and mental health can also be a problematic mix. Negative effects include:

• Mood swings

• Anxiety

• Hallucinations (seeing or hearing things that aren’t there)

• Depersonalisation (feeling detached from oneself)

• Paranoia

• Disorientation

• Impaired speech, memory, and focus

Is cannabis addictive?

Cannabis dependence is a recognised condition, known as Cannabis Use Disorder. Around 30% of regular cannabis users in the UK are believed to have developed this disorder, particularly those who began using it in adolescence or who use it daily.

Signs of dependence may include:

• Building a tolerance (needing more to achieve the same effects)

• Craving the drug

• Experiencing withdrawal symptoms such as irritability, restlessness, weight loss, nausea, mood swings, poor sleep, and lack of motivation or joy

Can cannabis trigger mental health problems?

A growing body of UK research has found associations between cannabis use and mental health conditions, including:

• Anxiety

• Depression

• Suicidal ideation (particularly in young people and veterans)

• Serious mental illness (e.g. schizophrenia)

High-THC cannabis can cause temporary psychotic episodes in some individuals. The relationship is likely bidirectional—people with psychosis may be more likely to use cannabis, while cannabis use may also increase the risk of psychotic disorders.

Genetics may also play a role in vulnerability to both cannabis use and mental illness.

Related: How to break free from weed: A comprehensive guide

Interestingly, a study at the Royal London Hospital revealed that those who consumed cannabis edibles were more prone to psychiatric symptoms and heart issues than those who smoked cannabis. Still, more data is needed to generalise these findings.

In summary, while there is a correlation between frequent cannabis use and poor mental health, causation has not been definitively established due to the complexity of contributing factors like:

• Early exposure

• Use of potent strains

• Pre-existing trauma or adverse childhood experiences (ACEs)

• Genetic predispositions

Physical health impacts of cannabis use

Cannabis doesn’t just impact mental health — it can also affect physical wellbeing.

Cancer

Some research suggests cannabis may help alleviate chemotherapy-related nausea. However, other studies have linked heavy cannabis use with testicular cancer, although more research is required.

Combining cannabis with tobacco — a common practice in the UK — significantly increases the risk of lung cancer.

Heart Health

Cannabis may cause increased heart rate and blood pressure immediately after use, possibly heightening the risk of stroke or heart disease. These risks are especially associated with smoking cannabis, as cannabis smoke contains harmful substances similar to tobacco.

Lung Function

Smoking cannabis, particularly with tobacco, may:

• Damage lung tissue

• Increase the risk of bronchitis

• Trigger persistent coughing and excess mucus production

The link between cannabis and diseases such as emphysema remains uncertain.

Related: Cannabis impacts sexual experience in multiple ways

Quitting cannabis: Support and guidance

If you’re looking to reduce or stop cannabis use, it helps to understand the underlying reasons for your use and what makes quitting difficult.

People who mix cannabis with tobacco may also develop nicotine dependence, which carries its own serious health risks, including heart disease and cancer.

Tips and Tools for Quitting

• Speak with a healthcare provider or stop-smoking advisor

• Consider nicotine replacement therapies

• Use prescribed medication to manage withdrawal symptoms

• Seek counselling to address emotional or psychological challenges

If you are using cannabis to cope with mental health issues, consult a mental health professional. Effective treatment may involve therapy, medication, exercise, and building a support network.

 

Disclaimer: The information provided on this page is for educational purposes only and should not be considered medical advice. Always consult with a healthcare professional before using any THC product.