Mind & body, in brief

Alzheimer's disease is the most common cause of dementia. Two proteins, amyloid and tau, can build up in the brain for more than 15 years before memory starts to fail. [5]

Lecanemab, made by Eisai, and donanemab, made by Eli Lilly, are antibodies: lab-made immune proteins that latch on to amyloid so the body clears it. [1][2]

Lecanemab got full US approval in 2023. [9] Both drugs were approved in the European Union in 2025 after a second review, only for people who do not carry two copies of a gene variant called APOE4. [2]

In the lecanemab trial, people on a dummy drug reached the same level of decline 6.1 months sooner than people on the drug, measured at 18 months. [2]

In April 2026 Cochrane, an international group that reviews medical evidence, pooled 17 trials in more than 20,000 people. It called the effect on memory and thinking trivial. [1]

Alzheimer's Research UK, a research charity, said only two of those 17 trials tested the drugs now in use, and the older, failed drugs shaped the result. [1]

NICE, which decides what England's health service pays for, said the drugs slow the illness by four to six months. [1] It refused to pay for them because the cost was too high, and is looking again after the makers appealed. [1]

The drugs can make the brain swell. On donanemab, swelling showed up on scans in 20.6% of people, against 1.8% on a dummy drug. On lecanemab it was 8.9% against 1.3%. [2]

In the UK, lecanemab is given as a drip every two weeks, with brain scans before the 1st, 5th, 7th and 14th doses to look for that swelling. [3]

In a three-year follow-up, donanemab cleared amyloid within about a year and a half in more than three in four people. Those who started early declined 1.2 points less on a dementia scale than untreated people in a separate study. [8]

Finding the illness is moving faster than treating it. Two blood tests are now cleared in the US, and one correctly rules out Alzheimer's 97.9% of the time. [4] Today only 2 in 100 patients are offered the scan or spinal test that confirms it. [5]

A blood marker called p-tau217 can now estimate when symptoms will start, with a typical error of three to four years. [6] In France about one in five people aged 65 to 85 without dementia already has amyloid in the brain. [7]

Why it matters. Watch what NICE decides on the makers' appeal, because that settles whether England's health service offers either drug. [1]

Scientists at the Climate Impact Lab at the University of Chicago estimate that heat from the current El Nino could cause 240,000 extra deaths between September and February. [10] El Nino is a natural warming of the eastern Pacific that pushes world temperatures up for about a year. [11] Adding the deaths they estimate since it began in June brings the total to about 450,000. [10] They expect more than 30,000 extra deaths in Nigeria, 19,000 in Indonesia, 16,000 in India and 13,000 in Brazil. [10]

Why it matters. Most of the coming deaths fall in the southern half of the world, where spring and summer are starting, and the oldest people are most at risk, then babies. [10]

Copernicus, the EU's climate service, said August 2026 tied July 2023 as the hottest month ever measured, at 1.65C above pre-industrial levels. [11] It ended western Europe's warmest summer on record, hotter than the deadly summer of 2003. [11] The UK had its hottest summer since records began in 1884. [11] Copernicus says the El Nino is still growing, so the run of records may go on. [11]

Why it matters. A heat researcher at Imperial College, a UK university, said the summer strained hospitals and cost tens of thousands of lives across the UK and Europe. [11] At least 35,000 extra deaths in Europe have been linked to this summer's heat. [10]

A study in Nature Climate Change looked at heatwaves on land around the world from 1979 to 2023. [12] Heatwaves now begin about 3.3 days earlier each decade and end about 5.4 days later. [12] The heatwave season has grown by about 8.7 days a decade, and got longer on 92% of the world's land. [12] Dry regions shifted most, and heatwaves have recently started arriving faster. [12]

Why it matters. The authors say heat warnings and heat plans need to plan for when heatwaves arrive, not only how strong they are. [12]

Researchers used social media posts and weather records from Chinese cities between 2010 and 2024 to measure how people felt during heatwaves. [13] They found 84.9% of cities had strong emotional shocks from heat, while 52.1% faced severe physical heat. [13] Poorer regions took longer to recover emotionally. [13] Physical resilience depended mostly on wealth and land cover, while mood depended more on how intense the heat was. [13]

Why it matters. The authors say heat plans should treat bodily harm and emotional strain separately, because the two do not line up. [13]

A study of more than 2,300 European cities looked at two things that raise heat deaths at the same time: the extra warmth of built-up areas, and populations growing older. [14] In summer, the two together raise heat deaths by 19% in 2030 and 58% in 2100 beyond what each would do alone. [14] In winter the extra city warmth cancels part of the extra cold deaths an older population would bring. [14]

Why it matters. Plans that count city heat and ageing one at a time will undercount summer deaths, the authors say. [14]

Australia banned under-16s from holding accounts on ten platforms, including TikTok, Instagram and YouTube, in December 2025. [17][16] A study in The BMJ followed 408 teenagers from just before the ban to about three months after. [15] More than 85% of under-16s were still using the banned platforms, mostly on their own accounts, and some used fake accounts or private browsers. [15] Daily use fell only among 14- and 15-year-olds, from 78% to 69%. [15]

Why it matters. The authors found little sign of an early drop in use and say the full effect may take a decade to show. [15] Platforms face fines of up to A$49.5m for serious breaches, while children and parents are not punished. [17]

The UK government plans to ban under-16s from some social media platforms, including TikTok and YouTube, with the ban expected by spring 2027. [18] Another minister told Parliament that under-16s will face some age or feature limits even if a full ban is not chosen, and curfews are being considered. [19] The European Union has chosen a different line, banning under-13s and personal accounts for under-15s. [16]

Why it matters. Researchers writing in STAT say the bans are a chance to measure what really changes for teenagers, such as sleep, friendships and study, not just screen time. [16] In the US, Meta, which owns Facebook and Instagram, agreed to pay up to $18 billion to settle claims that its apps harmed children. [16]

Chikungunya is a virus spread by mosquito bites that causes fever and joint pain. [20] The US Centers for Disease Control and Prevention counted 116 cases in US states in 2026 by 15 September, all linked to travel, and none caught locally. [20] In 2025, locally caught cases were reported in Florida and New York. [20] One vaccine, Vimkunya by Bavarian Nordic, is licensed in the US and recommended for travellers going to places with outbreaks. [21]

Why it matters. Local spread needs the right mosquitoes, and a study this year expects the Asian tiger mosquito, which carries the virus, to thrive further north as the climate warms. [23]

The Pan American Health Organization reported 313,132 chikungunya cases in 18 countries and one territory of the Americas in 2025, with 170 deaths. [22] Worldwide, 41 countries reported more than 500,000 cases that year. [22] The virus kept spreading into 2026 in parts of Brazil and southern Bolivia, and returned to the Guiana Shield in the north of South America. [22] By late January the region had counted 7,150 more cases. [22]

Why it matters. PAHO asked countries to keep testing and reporting cases, because the virus is turning up in places that had not seen it for years. [22]

A study in Frontiers in Cellular and Infection Microbiology found about 21% of the world's land, across 139 countries, is now suitable for the mosquitoes that spread chikungunya. [23] Under likely warming, northeastern North America, central Europe and East Asia could become hotspots by 2100. [23] The Asian tiger mosquito, which copes better with cooler weather, is expected to spread most. [23] Europe's disease agency counted about 33,000 cases worldwide by late May 2026, including nine deaths. [23]

Why it matters. Today, cases in Europe and North America are almost all in travellers coming home, which is why the US count has no local cases this year. [23][20]

Emmanuel Mignot and Masashi Yanagisawa won one of this year's Lasker Awards, prestigious prizes for medical research. [24] Working separately from the late 1990s, both found that orexin, a brain chemical, is central to narcolepsy, an illness of uncontrollable sleepiness. [24] Their work laid the ground for new wakefulness drugs that companies are racing to bring to market. [24] Other awards went to Japanese scientists for a haemophilia A treatment and to the actor Michael J. Fox for his Parkinson's work. [24]

Why it matters. Lasker Awards often come before a Nobel Prize, and the orexin drugs are chasing a market that STAT puts at $5 billion. [24]

A study led by Josef Coresh at New York University followed 12,409 Americans from age 55 in the early 1990s to 2022. [25] It looked at three risks to blood vessels: diabetes, high blood pressure and smoking. [25] People with none lived about 30 years past 55 without dementia, and people with all three about 17 years. [25] Women lived 1.5 to three years longer without dementia than men with the same risks. [25]

Why it matters. Black participants lived about three fewer dementia-free years than White participants. [25] The study shows a link, and the researchers say more work is needed on what changing these risks does. [25]

A study in the journal Alzheimer's and Dementia estimated that 5.7 million US adults aged 51 and over are living with dementia in 2026, helped by 5.2 million care partners. [26] It put the total cost at $818 billion. [26] The biggest part, $320 billion, is lost quality of life for people with dementia. [26] Unpaid care by family and friends adds $237 billion, and families carry more than three times the cost that health systems do. [26]

Why it matters. The authors say new treatments may raise medical bills while easing the load on carers. [26] A US cost study found lecanemab is not good value for money at the price its maker charges. [9]

Writing for World Alzheimer's Day on 21 September, doctors in the Indian Journal of Medical Research set out how India could prevent dementia. [27] A national survey estimated about 8.8 million Indians over 60, or 7.4%, have dementia, more of them in villages and among people with little schooling. [27] The 2024 Lancet Commission, a panel of dementia experts, estimated nearly 45% of dementia worldwide could be prevented or delayed by tackling 14 risks. [27] For India the estimate is up to 70%. [27]

Why it matters. The biggest risks in India are little schooling, poor eyesight, lack of exercise and isolation. [27] With no affordable cure, the authors say prevention is the realistic plan, as numbers head for about 11 million by 2050. [27]

Researchers tested 492 older adults in India on memory, language and planning, and asked about the languages they speak. [28] Most learned a second language, usually Hindi, as children. [28] Speaking the second language well was linked to better planning and decision-making, both in people with schooling and in people without. [28] Learning it early was linked to better language skills among people who never went to school. [28]

Why it matters. The study measured people once, so it shows a link rather than proof that languages protect the brain. [28]

The ELAD trial gave 204 people with mild to moderate Alzheimer's and no diabetes daily injections of liraglutide, a diabetes and weight-loss drug, or a dummy drug for a year. [29] Its main goal was a change in how much sugar the brain burns, seen on a scan, and it found no change between the groups. [29] One secondary score, on planning and thinking, came out better on the drug. [29]

Why it matters. Liraglutide acts like a natural hormone called GLP-1, and in mice bred to get an Alzheimer's-like disease it improved memory, which is why it was tried. [29]

XPro1595 blocks one harmful form of TNF, an immune signal that drives inflammation. It was tested in 207 people with early Alzheimer's for 24 weeks. [30] Across the 200 with results, it made no difference to its main thinking score. [30] In a group of 100 chosen in advance because they had amyloid and high inflammation, results leaned towards the drug on thinking and on agitation. [30] No brain swelling was seen. [30]

Why it matters. Unlike the amyloid drugs, it caused none of the brain swelling that needs repeat scans. [30][2] Because the smaller group was named before the trial began, the authors say the drug is worth testing in people with high inflammation. [30]

Researchers searched health records from four US hospital networks for 122,972 people aged 50 and over with mild memory problems. [31] They checked whether starting any of 181 common drugs was linked to a slower slide into dementia. [31] Twenty were, including the painkiller celecoxib and the stomach drug famotidine, and the pattern held in a second set of records. [31] The authors call them candidates for trials, not proven treatments. [31]

Why it matters. Using drugs that are already approved is a faster and cheaper route than building new ones, the authors say. [31]

Repetitive transcranial magnetic stimulation, or rTMS, stimulates the brain with magnetic pulses from outside the head. [32] A review of 14 trials in mild to moderate Alzheimer's found most reported better thinking scores after 4 to 12 weeks of sessions. [32] Side effects were mild, such as headaches and scalp discomfort. [32] But the trials were small, short and used very different settings. [32]

Why it matters. The authors conclude rTMS is not ready for routine care and call for larger trials that compare it with fake stimulation. [32]

Researchers in Tochigi, Japan, used insurance records for 8,117 people aged 65 and over with severe Alzheimer's who started an older type of Alzheimer's drug. [33] People on pills stayed on it for 1.5 years on average, against 0.6 years on skin patches. [33] Patch users were 11 times more likely to stop. [33] Hospital stays and deaths were lower in the pill group. [33]

Why it matters. The authors note there is little evidence these drugs help in severe Alzheimer's, so long use of the pills raises its own questions. [33]

A team led by Hansruedi Mathys, Zhijun Duan and Jian Ma studied brain tissue from 20 people aged 75 or older, half of whom had Alzheimer's. [34] They looked at how DNA folds up inside cells from the front of the brain. [34] In Alzheimer's, distant parts of the DNA sat together more often and neighbouring parts less often. [34] Tightly packed, switched-off DNA mixed more than usual with the loose, active kind. [34]

Why it matters. How DNA folds decides which genes a cell can use, so the change may help explain the altered gene activity seen in Alzheimer's and in ageing. [34]

In a Nature Medicine study of 337 people at seven centres, a few drops of blood from a finger prick, dried on a card, were tested for p-tau217, a marker of Alzheimer's. [35] The levels matched normal blood samples closely and picked out people with Alzheimer's changes in their spinal fluid with good accuracy. [35] A larger trial, Bio-Hermes-002, is now testing a finger-prick test in 1,000 volunteers over 60 in the UK, US and Canada. [5]

Why it matters. Waits to see a specialist in the US can run for months or more than a year, so a test a family doctor can use matters. [43] The Nature Medicine authors say the card method still needs work before clinics use it. [35]

Researchers read genetic material called RNA in the blood of 816 people without memory problems and 405 with Alzheimer's. [36] They found 34 circular RNAs, stable loops that can cross from the brain into the blood, linked to the disease. [36] A model built on those 34 did about as well as p-tau217, the best-studied blood marker. [36]

Why it matters. Catching the illness before symptoms is what the new treatments need, the authors say, and this adds a second kind of blood test to the protein tests now reaching clinics. [36]

A Nature Health study looked at 33 million deaths among white US adults aged 30 to 79 from 1992 to 2024. [37] For men with little schooling, the risk of dying between 30 and 79 rose from 65% to 79%. For men with the most schooling it fell from 44% to 34%. [37] Smoking caused 63% of the 3.2 million extra early deaths among people with less schooling. [37]

Why it matters. Among people under 65, opioids caused 3% of those extra deaths, rising to 8% in 2010 to 2019. [37] The authors call smoking the leading reason survival among white US adults has stalled. [37]

The World Health Organization says tobacco kills an estimated 164,000 people a year in Pakistan and costs about $6.6 billion. [38] That damage is seven times what the tobacco industry pays in tax there. [38] Pakistan has not raised its duty on cigarettes since February 2023, so they have become more affordable. [38] Worldwide, at least 40 million children aged 13 to 15 use tobacco. [38]

Why it matters. WHO says higher tobacco taxes cut smoking and raise money for health at the same time, and Pakistan's are below the 75% of the price it recommends. [38]