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Summary: Yes, cannabis use can increase paranoia. A recent study shows that cannabis use can increase paranoia and symptoms of mental health disorders, and that individual reasons for first using cannabis (RFUC) can affect the presence of mental health symptoms.

Key Points:

  • Reasons for first using cannabis (RFUCs) influence later presentation of mental health symptoms in people who continue to use cannabis
  • RFUCs influence reasons for continuing to use cannabis (RCUCs)
  • People who start using cannabis to ease mental health issues such as depression or anxiety show high levels of overall cannabis consumption
  • People who start using cannabis to ease physical discomfort or relieve pain show moderate levels of weekly cannabis consumption

Cannabis Use and Mental Health

The connection between excess, chronic cannabis use and mental health is well-documented. To read our previous articles on the topic, please navigate to our blog and read these posts:

Studies Link Cannabis Use with Mental Health Disorders

Cannabis, Psychosis, and Dopamine: What’s the Connection?

Data from those articles indicates that people who regularly use cannabis are at increased risk of:

  • Schizophrenia
  • Bipolar disorder
  • Depression

In addition, those articles outline an increased risk of hallucinations and delusions associated with schizophrenia among people who use cannabis. Those results are an initial indication that cannabis use can increase paranoia, since paranoia is a common category of delusion among people with schizophrenia, and people with schizophrenia who use cannabis increased risk of delusions and psychotic symptoms.

In this article, we’ll review the results of new research on the connection between cannabis use, initiation of cannabis use, continuing cannabis use, and how reasons for initiating cannabis use and continuing to use cannabis impact how cannabis use can increase paranoia.

Let’s take a look at the study.

Reasons for Cannabis Use Associated With Increased Paranoia and Other Mental Health Symptoms

In the largest study on the topic to date, a groups of researcher in the United Kingdom (U.K.) designed a review analysis called “Are Reasons for First Using Cannabis (RFUCs) Associated With Subsequent Cannabis Consumption and Psychopathology? In order to accomplish the following four research goals:

“(1) examine common, RFUCs, (2) identify their associations with reasons for continuing cannabis use, (3) weekly THC (delta-9-tetrahydrocannabinol) unit consumption and (4) symptoms of paranoia, anxiety and depressive symptoms.”

Researchers analyzed data from the Cannabis & Me (CAMe) population survey conducted between March 2022 and July 2024, which included data from 3389 current and/or former cannabis users over age 18 with no history of psychosis or diagnosis of a mental health disorders with psychotic features.

For baseline information on demographics and general physical health, participants completed a 40-minute introductory survey. Next, to determine baseline mental health circumstances, participants completed standardized mental health assessments, including:

In addition, all patients completed the Cannabis Experiences Questionnaire (CEQ), which posed the following core questions about cannabis use.

First, the survey posed this question:

“Why did you first try cannabis?”

Participants chose from the following answers:

  1. Friends were using it
  2. Family members were using it
  3. To help with physical discomfort
  4. For relief from pain
  5. To help with anxiety symptoms
  6. To help with depressive symptoms
  7. For help managing experiences such like hearing voices and/or suspicion/paranoia
  8. Out of curiosity
  9. For fun
  10. Out of boredom.

Next, the survey posed this question:

“Why do you continue to use cannabis?”

Participants chose from the following answers:

  1. I like the effect, it gives me a buzz
  2. I feel relaxed
  3. It makes me feel less nervous and anxious
  4. I feel more sociable
  5. Other

Finally, researchers assessed frequency of cannabis use with the following scale:

  • Never/hardly ever: 0
  • Monthly or less: 1
  • Weekly or less: 2
  • More than once a week: 3
  • Daily: 4

And assessed total cannabis consumption through verified self-report scales that label one unit (1) of THC as 5 milligrams, as confirmed by the U.S. National Institutes of Health (NIH).

Let’s take a look at what they found.

Cannabis Use: Increase in Paranoia, Anxiety, Depression

First, we’ll share several facts we don’t report in the information above or the results below. The average age at first was use of cannabis was 16.7 years old, over half the participants consumed cannabis daily, three-quarters consumed cannabis more than once a month, and roughly one quarter of participants no longer used cannabis.

With those general facts in mind, we’ll report the results in order of the research objectives/goals as defined by the research team, which we list above.

Data set one: Reasons for First Using Cannabis: RFUCs.

Research Goal 1: Identify Reasons for First Using Cannabis (RFUCs)

  • Friends using: 69.8%
  • Curiosity: 62.3%
  • Fun: 52.7%
  • Reduce anxiety: 15.4%
  • Reduce depression: 13.8%
  • Decrease boredom: 11.8%
  • Family using: 10.5%
  • Reduce pain: 7.6%
  • Reduce physical discomfort: 6%
  • Address symptoms of psychosis: 0.9%

We’ll take a moment to note the significant influence of peers on the reason to start using cannabis. We’ll also note that friends, family, and fun outpace all other reasons for initiating cannabis use, at percentages far higher than those associated with self-medication to ease mental health symptoms.

No for data set two: Reasons for Continuing Using to Use Cannabis: RCUC.

Research Goal 2: Identify Reasons for Continuing to Use Cannabis (RCUC)

  • Felt relaxing: 81.2%
  • Made me feel less nervous: 51.3%
  • I like the buzz/intoxicating effect: 47.5%
  • Made me feel more sociable: 27.1%
  • Other: 19.0%

We note here that the top two reasons for continued use are likely connected to mental health, but the nature of the questions and study confine that observation to the fact that cannabis use made people feel more relaxed/less nervous, which could both indicate satisfaction with a reduction in mental health symptoms. However, that’s our analysis of the first two bullet points above, rather than an explicit finding reported in the data.

Next, data set three: Weekly Cannabis Consumption.

Research Goal 3: Identify Weekly Cannabis Consumption

Mean weekly cannabis consumption:

  • 206 THC units
    • 1030 milligrams per week

For perspective:

  • THC content, standard gummy or edible:
    • 20-25 milligrams, or 4-5 units
  • THC content, cigarette or joint:
    • 40 milligrams, or about 8 units

In common usage:

  • Mean weekly consumption is roughly equivalent to:
    • About 20-25 joints
    • About 40 gummies

Note: mean weekly usage identified in this study is far higher mean weekly usage identified in other studies on weekly cannabis consumption.

Next, data set four: Connections Between RFUC and Mental Health Outcomes.

Research Goal 4: Identify Associations Between RFUC and Mental Health

By RFUC, mental health outcomes:

      • Friends:
        • No association with higher scores on mental health metrics
      • Family:
        • Higher depression scores
      • Physical discomfort:
        • Higher paranoia, anxiety, and depression scores
      • Pain:
        • Higher paranoia, anxiety, and depression scores
      • Anxiety:
        • Higher paranoia, anxiety, and depression scores
      • Depression:
        • Higher paranoia, anxiety, and depression scores
      • Psychosis:
        • Higher paranoia, anxiety, and depression scores
      • Curiosity:
        • Higher paranoia scores
      • Fun:
        • Higher paranoia and anxiety scores
      • Boredom:
        • Higher paranoia and depression scores

This dataset is interesting for two reasons. First, the most common reason for starting cannabis use – friends using – was not associated with any negative mental health outcomes. Second, less common reasons for starting cannabis use, including physical discomfort, were associated as strongly with negative mental health outcomes as starting cannabis use to alleviate mental health symptoms.

We’ll discuss these results below.

Cannabis Use and Increase in Paranoia: Part of a Large Picture

Here’s a summary of what we learned from the data above. We’ll note that the most common reasons for initiating cannabis use and reasons for continuing cannabis use appear unrelated to mental health concerns, with the exception of continuing because it made individuals feel less nervous, which showed a mild correlation with symptoms of anxiety and symptoms of depression.

Primary Takeaways: All Metrics

  • Participants with RFUC for pain or physical discomfort were associated with continued use for mental health reasons
  • Participants with RFUC for any mental health reasons were associated with continued use for mental health reasons
  • RFUC to reduce any mental health or physical discomfort:
    • Higher scores on anxiety metrics
    • Higher scores on depression metrics
    • Highest scores on paranoia metrics
  • THC consumption by RFUC:
    • Family, anxiety, depression: high level of weekly consumption
    • Pain, discomfort: moderate level of weekly consumption

One interesting aspect of these results is the fact that people who both initiated and continued cannabis use for casual, social, or recreational reasons – for fun, because friends were doing it, because family was doing it, or out of curiosity – showed significantly higher weekly use then people who initiated and continued use to alleviate physical, psychological, or emotional pain or discomfort. In addition, people who initiated cannabis use to address physical pain or emotional discomfort continued using cannabis for those same reasons.

Here’s how the study authors describe the study outcomes:

“Our findings, for the first time, provide evidence that people who start using cannabis to reduce psychological or physical discomfort differ from those who start for other reasons, and report higher average weekly THC unit consumption as well as higher levels of paranoia, anxiety and depression, compared to those who start for socializing, curiosity, and having fun.”

There we find a direct, unequivocal answer to the question we pose in the title of this article, Can Cannabis Use Increase Paranoia? The answer is yes, it cannabis use can increase paranoia, a phenomenon that appears predominantly in people who initiate cannabis use to help reduce symptoms of anxiety and/or depression.

How This Information Can Help Our Patients

We regularly treat patients with serious mental health disorders, including schizophrenia, treatment-resistant depression, and bipolar disorders, all of which may include paranoid features and/or symptoms associated with paranoia.

When patients with mental health disorders use cannabis, we need to know.

Now we know that the more we know about how their cannabis use started, and why it continued, the better we can understand and help them manage mental illness.

In the U.S. in 2024, the National Survey on Drug Use and Health (2024 NSDUH) showed that just under 20 million adults over age 18 in the U.S. had a cannabis use problem, and that over 20 million people had a mental health disorder and a substance use problem.

In other words, millions of people need providers who understand how cannabis use may influence mental health. We’ll close this article with more insight from the study authors, who offer a compelling case for asking people with any kind of mental health disorder about the details around cannabis use:

“Asking people why they started using cannabis could become an easy and cheap tool, in clinical and non-clinical settings to identify users…who might benefit from monitoring, support or referral to intervention services to prevent a possible transition from moderately severe psychopathology to potentially disabling anxiety, depression and paranoia.”

About Angus Whyte

Angus Whyte has an extensive background in neuroscience, behavioral health, adolescent development, and mindfulness, including lab work in behavioral neurobiology and a decade of writing articles on mental health and mental health treatment. In addition, Angus brings twenty years of experience as a yoga teacher and experiential educator to his work for Crownview. He’s an expert at synthesizing complex concepts into accessible content that helps patients, providers, and families understand the nuances of mental health treatment, with the ultimate goal of improving outcomes and quality of life for all stakeholders.