Health

Study Links High-Potency Cannabis to Greater Risk of Psychosis and Addiction

Published

10 months ago

August 26, 2025

A sweeping new analysis has found that cannabis products with high levels of the psychoactive compound THC may significantly raise the risk of psychosis, schizophrenia, and addiction, heightening concerns among researchers and health officials as cannabis use rises worldwide.

The study, published in the Annals of Internal Medicine, reviewed 99 research papers conducted between 1977 and 2023, covering more than 220,000 people. It concluded that products containing higher concentrations of delta-9-tetrahydrocannabinol (THC) — the chemical responsible for the “high” associated with cannabis — are strongly linked to serious mental health risks.

In Europe, cannabis remains largely illegal, but the European Union Drugs Agency (EUDA) estimates that 4.3 million people use the drug daily or nearly every day. Consumption spans smoking herbal marijuana, eating edibles such as gummies, and vaping potent concentrates like hash oil, “shatter,” and “dabs.”

The potency of these products has increased sharply in recent years. In 2023, cannabis resin in Europe had an average THC concentration of 23%, compared with 11% for herbal cannabis, according to the EUDA. By comparison, researchers considered products with THC levels above 10% or 5 milligrams per serving to be “high-potency.”

The review found that people using such products faced an elevated risk of psychosis and schizophrenia within hours of consumption. Long-term use was also tied to cannabis use disorder — a form of addiction — as well as respiratory problems and dependency symptoms.

“There’s a real warning in these findings,” said Dr. Jonathan Samet, a co-author of the study and professor of epidemiology at the Colorado School of Public Health. “We really need to be carefully watching what the consequences of these products are.”

Findings for more common mental health conditions, such as anxiety and depression, were mixed. Some evidence suggested high-potency THC could ease symptoms in patients with cancer or neurological disorders, but other studies identified harmful effects. Overall, researchers cautioned that the benefits were limited and often tied to specific medical conditions.

The EUDA has long warned that frequent and heavy cannabis use can exacerbate psychiatric problems, increase dependence, and worsen lung health. The new findings, while not yet definitive, reinforce these concerns and could influence future regulations.

Samet noted that any attempt to regulate THC levels would face challenges, since consumers could simply adjust their dosage. “There’s not a simple solution when it comes to potency,” he said. Still, he argued that greater awareness is essential, especially for those with existing mental health vulnerabilities.

“People who say, ‘Well, I’m using THC, what about it?’ … need to know that there are risks,” Samet added.

Health

Study Finds Men Far More Likely Than Women to ‘Hit the Wall’ in Marathons

Published

2 days ago

July 4, 2026

Web Reporter

Men are significantly more likely than women to experience the dreaded marathon phenomenon known as “hitting the wall,” according to a large international study that analysed the performances of more than 870,000 runners over a 26-year period.

The research, published in the journal Scientific Reports, examined the results of 873,334 finishers in the Berlin Marathon between 1999 and 2025. Researchers found that although men generally complete marathons faster than women, they are much more likely to suffer a dramatic slowdown during the later stages of the race because of less consistent pacing.

According to the study, men are almost twice as likely overall to experience a sudden decline in speed during a marathon. In some performance categories, they were found to be up to six times more likely than women to “hit the wall,” a term commonly used to describe severe physical exhaustion caused by depleted energy stores.

Researchers said the findings point to differences in race strategy rather than physical ability alone. Men were more likely to begin races at an aggressive pace, increasing the risk of fatigue before reaching the finish line.

The study concluded that “men, regardless of performance level, are more prone to aggressive pacing and catastrophic deceleration.” The authors suggested that greater willingness to take risks and higher levels of confidence may encourage many male runners to start faster than they can realistically sustain over the full 42.195-kilometre distance.

Women, on the other hand, displayed more controlled pacing throughout the race. Researchers found they were better at regulating their effort from start to finish, reducing the likelihood of a significant loss of speed during the closing kilometres.

The report described women as showing “superior self-pacing abilities and greater resistance to decision-making fatigue,” characteristics that can be particularly valuable during endurance events.

Maintaining a steady pace is widely regarded as one of the most important factors in marathon performance. Running too quickly during the opening stages can rapidly consume the body’s glycogen reserves, leaving athletes without enough energy to sustain their speed in the final part of the race.

The researchers noted that pacing is “the most critical tactical determinant of performance” in marathon running, making strategic decision-making just as important as physical fitness.

The findings could influence how coaches and runners prepare for long-distance races. Rather than focusing solely on speed, the study suggests that adopting a realistic race plan and maintaining a consistent pace throughout the event may improve overall performance and reduce the chances of a late-race collapse.

With marathon participation continuing to grow worldwide, the researchers believe a better understanding of pacing strategies could help runners of all abilities achieve stronger and more consistent results.

Health

Study Links Higher Coffee Consumption to Lower Risk of Liver Disease

Published

3 days ago

July 3, 2026

Web Reporter

Regular coffee consumption may help reduce the risk of serious liver diseases, including cirrhosis, liver cancer and liver-related deaths, according to a new study published in the journal Clinical Gastroenterology and Hepatology.

The research found that people who consumed higher amounts of coffee, including decaffeinated varieties, were less likely to develop chronic liver conditions than those who drank little or no coffee. The findings add to growing evidence that coffee may play a role in supporting long-term liver health, although researchers stressed that the results do not prove a direct cause-and-effect relationship.

The study examined data from more than 350,000 participants enrolled in the UK Biobank, one of the world’s largest long-term health research projects. None of the participants had cirrhosis or liver cancer at the beginning of the study. Researchers monitored their health over a period of 13 years to assess how coffee consumption affected liver-related outcomes.

According to the findings, participants who drank five or more cups of coffee each day had a 32 percent lower risk of developing cirrhosis than those who consumed little or no coffee. They also recorded a 47 percent lower risk of liver cancer and a 42 percent reduction in deaths linked to liver disease.

Researchers found additional indicators of improved liver health among regular coffee drinkers. Participants with higher coffee intake showed lower levels of liver fat, liver iron, fibrosis and inflammation. Blood tests also revealed increased levels of proteins associated with healthy liver function, while markers linked to liver scarring and inflammation were generally lower.

The findings come as liver disease continues to pose a major global health challenge. A separate study published in 2023 estimated that liver disease causes around two million deaths each year, accounting for about four percent of all deaths worldwide. Men account for nearly two-thirds of those fatalities.

Despite the encouraging results, the researchers urged caution in interpreting the findings. Senior study author Ju Dong Yang said moderate coffee consumption appears to be beneficial for people who already enjoy drinking coffee and tolerate it well.

“Our findings support moderate coffee consumption for people who already enjoy and tolerate it well,” Yang said.

He added that the study does not provide sufficient evidence to recommend that people who do not currently drink coffee should begin doing so solely to reduce their risk of liver disease.

Health experts continue to advise that maintaining a healthy weight, limiting alcohol consumption, eating a balanced diet and managing conditions such as obesity and diabetes remain the most effective ways to reduce the risk of chronic liver disease. Researchers said additional studies are needed to better understand which compounds in coffee may contribute to its potential protective effects.

Health

Lancet Review Finds mRNA Vaccines Safe and Highly Effective, Calls for Wider Global Access

Published

5 days ago

July 1, 2026

Web Reporter

A comprehensive review of data covering billions of administered doses of mRNA vaccines has concluded that the technology remains both safe and highly effective in preventing infectious diseases, with researchers urging governments and health organisations to focus on expanding global access.

The review, published in The Lancet, examined evidence gathered since mRNA vaccines were first deployed on a large scale during the COVID-19 pandemic. Researchers found that the vaccines continue to provide strong protection against severe illness while serious side effects remain uncommon.

Unlike conventional vaccines, mRNA vaccines work by delivering genetic instructions that enable the body’s cells to produce a harmless viral protein. This process trains the immune system to recognise and respond to future infections without altering a person’s DNA.

According to the review, mRNA vaccines were 87% effective in preventing confirmed SARS-CoV-2 infections within 14 to 42 days after vaccination. The vaccines also demonstrated 93% effectiveness in preventing hospital admissions and 94% effectiveness in preventing deaths related to COVID-19 during the same period.

Researchers noted that immunity declines over time, but booster doses restore a significant portion of the lost protection.

The review also assessed vaccine safety across billions of administered doses. It found that serious adverse events, including myocarditis, pericarditis and anaphylaxis, occurred very rarely. Most reported reactions, such as pain at the injection site, fatigue and fever, were mild to moderate and typically resolved within a few days.

“Across billions of administered doses, serious adverse events have been rare, well characterised, and consistently outweighed by the substantial protection conferred against severe disease, hospitalisation, and death,” the researchers wrote.

The review concluded that the vaccines have proven effective across a broad range of populations, including children, older adults, pregnant women and people with weakened immune systems.

Researchers also highlighted the growing potential of mRNA technology beyond infectious diseases. They said ongoing research could lead to personalised cancer vaccines designed to match an individual patient’s tumour characteristics, opening new possibilities for targeted treatment.

Co-author Manish Sadarangani of the University of British Columbia and BC Children’s Hospital Research Institute said mRNA vaccines have already changed how the world responds to emerging infectious diseases and could continue to play an important role in preventive medicine and cancer care.

The review also noted that improvements in vaccine storage, including higher-temperature storage methods and freeze-drying technologies, could simplify transportation, reduce waste and improve access in remote regions.

Despite these advances, the researchers stressed that manufacturing capacity and equitable distribution remain major challenges. They called for greater investment in local production, technology transfer and stronger regulatory systems, particularly in low- and middle-income countries.

Co-author Robin Shattock of Imperial College London said expanding manufacturing networks and strengthening regional production capabilities would shorten supply chains, lower costs and help ensure countries have faster access to vaccines during future global health emergencies.