Cannabis and Depression - what does the science say?

It's no secret that cannabis has been used to treat depression for centuries. But with the recent legalisation of the plant in many parts of the world, including medical consumption in the UK, whether it's effective at treating the condition has come to the forefront. What does the research show about cannabis and depression?

Understanding Clinical Depression

First, let's look at what exactly defines clinical depression. According to the National Institute of Mental Health, depression is " a common but serious mood disorder. It causes severe symptoms that affect how you feel, think, and handle daily activities, such as sleeping, eating, or working.".

Depression can cause a host of symptoms, including fatigue, changes in appetite or sleep patterns, irritability, restlessness, and feelings of hopelessness. It can also lead to physical problems like headaches and aches and pains.

For many people, depression is a short-term problem that can be resolved with medication, therapy, or self-care. But for others, it can be a long-lasting condition that requires ongoing treatment. There is no one-size-fits-all solution for depression, but there are many treatments that can be effective.

Cannabis and Depression

You can't go far without someone pointing out the smiles and laughs from the potent plant. But depression is more than being in a bad mood. Depression is a serious mental illness that can have profound effects on every aspect of a person's life.

A review of the literature on cannabis and depression found some evidence supporting using cannabinoids to treat depression, but the evidence is inconclusive. Cannabis is effective in treating depression in some studies but not in others. It's important to note that bias in older studies can cause a negative result despite the research findings. So, reading the full report is necessary for a more accurate understanding of the study.

The studies that have been done on marijuana and depression have been small and not well-designed. This makes it difficult to draw firm conclusions about the efficacy of cannabis in treating depression.

That being said, there is some promising evidence that cannabis may be effective in treating depression. A report published in 2021 found that people with treatment-resistant depression who used marijuana significantly reduced their symptoms.

What Cannabis May Do For People With Depression

Serotonin is a neurotransmitter that plays a role in mood and emotion. Research has also shown the potent plant to have antidepressant effects in some studies. It's thought to work by increasing levels of serotonin in the brain.

Cannabis may also help relieve other symptoms of depression, such as anxiety, pain, and insomnia. The chemicals in cannabis may have anti-anxiety and analgesic (pain-relieving) effects.

Many people with depression also endure anxiety and may have chronic pain. Cannabis may be effective in treating both conditions. Research shows people with anxiety and depression who used cannabis significantly reduced symptoms.

Cannabis may also help improve sleep. Problems falling and staying asleep are common with depression.

How Does Cannabis and Depression Work?

Depression is a complex condition with multiple causes. Cannabis may work by affecting some of the brain's systems involved in depression.

The popular plant with cannabinoids affects the endocannabinoid system, which is involved in a variety of functions, including mood, hunger, and pain. The ECS may also play a role in depression by affecting serotonin levels.

Marijuana also affects the brain's serotonin. The vital neurotransmitter plays a role in mood and emotion. Low levels of serotonin are linked to depression. 

Cannabinoids bind to receptors in the brain, which may boost serotonin. This action could help lift a person's mood and relieve some symptoms of depression.

Cannabis may also have anti-inflammatory effects. Research has linked inflammation to depression. Cannabis may help reduce inflammation by affecting the endocannabinoid system. It's thought that the endocannabinoid system helps regulate inflammation in the brain.

Neuroinflammation is thought to be involved in depression. Cannabis may help reduce neuroinflammation by affecting the endocannabinoid system. Cannabinoids may also help protect nerve cells.

Cannabis and Depression: Does Strain Matter?

The cannabinoids in cannabis, including THC and CBD, have different effects on the brain. THC is the psychoactive compound that gets people "high." CBD is non-psychoactive and does not produce a "high."

Different strains of cannabis also contain different ratios of THC and CBD. Some strains are higher in THC, while others are higher in CBD.

Cannabis strains high in THC may be more effective in treating depression. Studies found that people who used THC-rich strains had a lower risk of depressive symptoms than those who didn't use cannabis.

However, higher THC levels can increase anxiety and paranoia. So, it's essential to start with a low dose and increase as needed slowly.

Cannabis strains high in CBD may also be effective in treating depression. A study published in 2010 found that CBD had antidepressant-like effects in animals.

CBD may help reduce anxiety, which is a common symptom of depression. CBD may also have anti-inflammatory and neuroprotective effects.

The popular and potent plant has over 500 compounds. Along with phytocannabinoids, it also contains terpenes. Terpenes are aromatic compounds that give cannabis its distinctive smell.

Terpenes may also have antidepressant effects. Reports found that terpenes had antidepressant-like effects. Limonene and myrcene, two common terpenes in cannabis, were especially effective.

Common Strains Consumers Use for Depression

Some popular strains that may help with depression include:

  • Blue Dream: This sativa-dominant hybrid has a high THC content. It's known for its uplifting and energetic effects.
  • Granddaddy Purple: This indica-dominant strain has a high THC content. It's reported to have relaxing and soothing effects.
  • Harlequin: This sativa-dominant strain has a high CBD content. It's known for its uplifting and anxiety-reducing effects.

Cannabis and Depression: The Bottom Line

Depression is a complex condition with multiple causes. It's clear the research supports that cannabis, specifically THC and CBD, can ease some symptoms of depression. Cannabis may affect some of the brain's systems involved in depression. For questions, consult a mental health professional or your primary care physician.