Marijuana and Mental Health: What We Know About the Risks and Benefits

Marijuana and mental health leave us with more questions than answers. THC and CBD may help or harm, depending on how, when, and why you use them. Here's what you need to know.

by Ashley Howell PMHNP

Does Marijuana Help or Hurt Mental Health?

The relationship between marijuana and mental health is one of the most hotly debated topics in psychiatry today. For some, it feels like a lifesaver. For others, it's the root of worsening symptoms. So, which is it—helpful or harmful?

The answer is complicated.

Why This Question Is Hard to Answer

Cannabis is a complex plant containing over 500 chemical substances. Two compounds are especially relevant for mental health: THC (tetrahydrocannabinol) and CBD (cannabidiol). THC is responsible for marijuana's psychoactive effects—the "high"—while CBD is believed to offer calming, neuroprotective benefits.

Every person’s brain chemistry, genetic background, and mental health needs are different, which means marijuana affects everyone differently. That variability makes it difficult to say marijuana is universally helpful or harmful.

THC vs. CBD: What’s the Difference in Mental Health Effects?

Here’s a simplified breakdown of how these two compounds interact with the brain:

THC: Responsible for the high, THC can reduce pain, nausea, and sometimes depression, but it may also trigger anxiety, paranoia, or even psychosis in high doses. It increases the heart rate and has sedative effects.
CBD: Does not cause a high. It has anti-anxiety, antipsychotic, and neuroprotective properties. CBD may help ease depression, reduce seizures, and regulate heart rate.

In combination, CBD may reduce some of the unwanted effects of THC. However, modern marijuana strains are often bred for higher THC content and lower CBD, increasing the risk of adverse mental health effects.

Today’s Weed Is Stronger—and Riskier

The marijuana used today is much more potent than it was a generation ago. In 1995, THC content averaged 4%. Today’s cannabis averages 15%, with concentrates often exceeding 70% or even 90%.

This sharp increase in potency makes it easier to overconsume and harder to predict individual reactions, especially when someone is trying to self-medicate for depression, anxiety, or PTSD.

Can Cannabis Help With Depression or Anxiety? Maybe.

Some studies suggest THC can have antidepressant effects at low doses. But go above that "sweet spot," and symptoms may worsen. Even more concerning, THC may reduce depression while increasing anxiety, and these two conditions often co-occur.

So, someone using marijuana to treat depression might unknowingly make their anxiety worse. If their anxiety goes unrecognized, they might interpret the worsening symptoms as a failure of cannabis or themselves.

CBD Might Reduce Harm—But It's Disappearing

CBD can decrease anxiety, reduce psychosis risk, and even regulate heart rate—all effects that counterbalance THC. Unfortunately, most modern cannabis strains and concentrates are bred for higher THC, with diminishing amounts of CBD.

This skewed THC-to-CBD ratio is likely contributing to increases in cannabis-induced anxiety, paranoia, or even psychosis in some users.

What Science Says About Marijuana and Psychosis

Longitudinal research shows a clear connection between frequent cannabis use and increased risk of psychotic disorders like schizophrenia, especially in adolescents and young adults.

One study found that individuals who used cannabis daily before age 18 were five times more likely to develop schizophrenia than those who didn’t. High-potency products increase this risk.

For individuals already predisposed to psychosis (due to genetics or early symptoms), cannabis use can worsen symptoms and lead to more hospitalizations and relapses.

Emotional Blunting and Teen Brain Development

THC impacts the prefrontal cortex—the part of the brain that governs decision-making, emotional regulation, and impulse control. Chronic cannabis use can lead to slower emotional processing and difficulty managing relationships.

In teens, whose brains are still developing, this can mean lasting impairments. Early, frequent cannabis use is also linked to lower academic achievement, higher risk of depression, and increased social anxiety.

Is Self-Medicating with Marijuana Safe?

Not always. Many people turn to marijuana for symptom relief, especially if they’re dealing with trauma, depression, or social anxiety. But using cannabis to self-medicate can delay evidence-based treatments and worsen symptoms over time.

A 2024 study found that people who visited the ER for cannabis use were nearly 4x more likely to develop an anxiety disorder within three years. And those already diagnosed were 9x more likely to be hospitalized again for anxiety compared to the general population.

What to Tell Your Mental Health Provider About Cannabis

At Axis Integrated Mental Health, we welcome honesty. Many of our patients use marijuana, and they’re never judged for it. In fact, the more we know, the better we can help.

We ask about your cannabis use not to criticize, but to understand. How much are you using? What type of products? Are you trying to manage symptoms? Are you experiencing side effects like paranoia or mood swings?

These details help us individualize your care and keep you safe.

Moderation, Honesty, and Harm Reduction: The Bottom Line

Marijuana isn’t all good or all bad. It’s a complex substance that can help some people and harm others. What matters most is how it's used, in what amounts, and for what purpose.

Moderation and transparency with your care team are key. If you're struggling with mental health symptoms and also using cannabis, talk to someone you trust.

We’re here to listen. We’re here to help.