Key Takeaways 

• Broad temporal and population spectrum on cannabis use & mental health.
• Cannabis linked to depression, anxiety and suicidal tendencies in studies.
• Early cannabis use in youth leads to mental health issues in adulthood.
• Systematic review and meta-analysis updates cannabis mental health risks evidence.

Abstract: Cannabis is the most widely consumed illicit drug globally. In 2021, 46 % of countries identified cannabis as the predominant substance associated with drug abuse disorders, with 34 % indicating it as the primary cause for seeking treatment. Young individuals represent the largest consumer demographic, experiencing substantial negative health effects. Despite extensive research on its mental health impacts, many aspects remain unclear. This study examines cannabis use among young people including anxiety, depression, and suicidal behavior. Studies involving individuals aged 15–30 were included. Data sources included PubMed, Mendeley, Embase, WOS, CINAHL, and Scopus. After screening 6466 articles, 36 met the inclusion criteria, with 18 included in the meta-analysis. These studies were published between 2013 and 2025. The results indicated that the odds of depression were 51 % higher in young cannabis users (OR = 1.51, 95 %CI = 1.23–1.86), decreasing to 28 % after adjustment (aOR = 1.28, 95 %CI = 1.10–1.50). Anxiety showed a 58 % increase (OR = 1.58, 95 %CI = 1.15–2.15). For suicidal ideation, the increase ranged from 50 % in unadjusted models (OR = 1.50, 95 %CI = 1.05–2.14) to 65 % in adjusted models (aOR = 1.65 95 %CI = 1.40–1.93). Finally, the odds of suicide attempt were 87 % higher (OR = 1.87, 95 %CI = 1.25–2.80), remaining elevated at 80 % after adjustment (aOR = 1.80, 95 %CI = 1.30–2.49).

(Complete Research - Source: Science Direct )

New research reveals a stark warning for cannabis users: marijuana significantly increases the risk of dangerous heart rhythm problems that can prove fatal.

A large-scale study published in August 2025 by researchers from the University of California, Georgetown University, and multiple other medical institutions found that cannabis use substantially raises the likelihood of developing serious cardiac arrhythmias. The findings show cannabis users face more than triple the risk of ventricular tachycardia and ventricular fibrillation compared to non-users.

Understanding the Risk

The retrospective study analysed electronic health records from 68 U.S. healthcare organizations, examining over 210,000 cannabis users matched with a similar number of control subjects. Researchers found 97 cases of ventricular tachycardia or fibrillation among cannabis users versus only 35 cases in the control group, representing a hazard ratio of 3.078.

Ventricular arrhythmias represent the most severe type of irregular heartbeat. These conditions occur when the heart’s lower chambers beat too quickly or chaotically, potentially preventing the heart from pumping blood effectively. Without immediate treatment, ventricular fibrillation can cause sudden cardiac death within minutes.

Beyond Ventricular Arrhythmias

The study documented elevated risks across multiple types of heart rhythm disorders. Cannabis users showed 1,895 cases of atrial fibrillation or flutter compared to 1,332 in the control group, with a 55% increased risk. Paroxysmal tachycardia occurred in 1,065 cannabis users versus 672 controls, representing a 79% increased risk, while premature beats affected 1,135 cannabis users compared to 745 controls, a 74% increase.

Atrial fibrillation emerged as the most common arrhythmia among cannabis users, though less immediately dangerous than ventricular arrhythmias. Atrial fibrillation still carries serious consequences, including increased stroke risk and heart failure.

Why Cannabis Affects Heart Rhythm

Multiple mechanisms may explain how cannabis triggers arrhythmias, including THC’s ability to block cardiac ion channels and prolong the QT interval. THC also enhances sympathetic nervous system activity through CB1 receptor activation, increasing heart rate and susceptibility to irregular rhythms.

Cannabis can cause coronary vasospasm and endothelial dysfunction, creating conditions that promote arrhythmias. Chronic use may lead to cardiac inflammation and fibrosis, causing atrial remodelling directly linked to atrial fibrillation development.

Research suggests the highest risk period occurs within one to two hours after cannabis use, indicating acute exposure poses immediate danger.

A Growing Public Health Concern

As cannabis legalization expands, hospitalization rates for cannabis-related arrhythmias have increased 31% over the past decade. The rise in arrhythmia-related hospitalizations appears particularly pronounced among teenage cannabis users.

Cannabis-induced arrhythmias disproportionately affect young, otherwise healthy individuals without structural heart disease, challenging assumptions that heart rhythm problems primarily afflict older adults with existing cardiovascular conditions.

The study used propensity score matching to ensure fair comparison between groups, accounting for age, sex, cardiovascular risk factors, and medication use. This rigorous methodology strengthens confidence in the findings.

What This Means for Users

Healthcare providers should counsel patients about cardiovascular risks associated with cannabis, particularly those with pre-existing heart conditions. The cardiovascular effects of marijuana deserve serious consideration as legal access continues expanding nationwide.

For individuals using or considering cannabis, these findings provide important context. Heart arrhythmias represent serious medical emergencies requiring immediate attention. Anyone experiencing symptoms like rapid heartbeat, chest pain, dizziness, or fainting should seek medical care promptly.

The research adds to mounting evidence documenting adverse cardiovascular effects of cannabis use. As the scientific community continues investigating these risks, current data already provide clear cause for concern about marijuana’s impact on heart health.

Source (WRD News)

(An Ed Sheeran moment!)

The Turning Point: In a revealing poem featured in the collection, Matthew McConaughey describes how cannabis evolved from recreational enjoyment into something far more problematic. Matthew McConaughey quitting cannabis represents a significant shift in his personal journey. He recounts the contrast between earlier experiences with the drug and its deteriorating effects over time.

McConaughey explains that what began as casual cannabis use became increasingly detrimental to his functioning. Rather than providing inspiration, the substance began causing paralysis and obsessive overthinking. He describes finding himself fixated on trivial details for extended periods, convinced they held significance when they did not.

A Catalyst for Change: A particularly striking moment prompted his reassessment of cannabis dependence. Matthew McConaughey reveals that on one occasion, he became so engrossed in listening to music whilst under the influence that he missed his own birthday celebration entirely. This incident underscored how cannabis had begun interfering with his ability to engage meaningfully with life. (Full Story  WRD News)

Interest in the use of cannabis and cannabinoids to treat chronic non-cancer pain is increasing, because of their potential to reduce opioid dose requirements. We aimed to investigate cannabis use in people living with chronic non-cancer pain who had been prescribed opioids, including their reasons for use and perceived effectiveness of cannabis; associations between amount of cannabis use and pain, mental health, and opioid use; the effect of cannabis use on pain severity and interference over time; and potential opioid-sparing effects of cannabis.

Findings: 1514 participants completed the baseline interview and were included in the study from Aug 20, 2012, to April 14, 2014. Cannabis use was common, and by 4-year follow-up, 295 (24%) participants had used cannabis for pain. Interest in using cannabis for pain increased from 364 (33%) participants (at baseline) to 723 (60%) participants (at 4 years). At 4-year follow-up, compared with people with no cannabis use, we found that participants who used cannabis had a greater pain severity score (risk ratio 1·14, 95% CI 1·01–1·29, for less frequent cannabis use; and 1·17, 1·03–1·32, for daily or near-daily cannabis use), greater pain interference score (1·21, 1·09–1·35; and 1·14, 1·03–1·26), lower pain self-efficacy scores (0·97, 0·96–1·00; and 0·98, 0·96–1·00), and greater generalised anxiety disorder severity scores (1·07, 1·03–1·12; and 1·10, 1·06–1·15). We found no evidence of a temporal relationship between cannabis use and pain severity or pain interference, and no evidence that cannabis use reduced prescribed opioid use or increased rates of opioid discontinuation.

Interpretation: Cannabis use was common in people with chronic non-cancer pain who had been prescribed opioids, but we found no evidence that cannabis use improved patient outcomes. People who used cannabis had greater pain and lower self-efficacy in managing pain, and there was no evidence that cannabis use reduced pain severity or interference or exerted an opioid-sparing effect. As cannabis use for medicinal purposes increases globally, it is important that large well designed clinical trials, which include people with complex comorbidities, are conducted to determine the efficacy of cannabis for chronic non-cancer pain.

(Source: The Lancet – Public Health  https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(18)30110-5/fulltext)

Also see

• Cannabis and Pain – Helpful – What is the Evidence?
• Academic concerns around Cannabis and Pain Management 

Unintentional marijuana ingestions in children under 5 rose over 1,000% in 7 years, with edibles and pandemic-related factors fuelling the trend.

Unintentional marijuana ingestions among children younger than 5 years have risen more than 1,000% in the past seven years, according to research presented at the American Academy of Paediatrics (AAP) 2025 National Conference & Exhibition in Denver, Colorado.^1,2

The retrospective study, Rising Trends in Paediatric Marijuana Ingestions: A Retrospective Analysis of the Impact of COVID-19 on Emergency Department Presentations, reviewed over 2,300 paediatric emergency department (ED) cases from 2016 through 2023. Researchers found sharp increases in exposures during the COVID-19 pandemic, with children most often consuming cannabis edibles that resembled candy.

“Even young children in states where marijuana is not legal are being hospitalized after unintentionally ingesting cannabis products—often edibles that look like candy,” said study author Brittain Robinson, MD, FAAP, of the University of Tennessee Health Science Center.

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