A person’s sleeping brain may reveal warning signs of dementia long before memory problems begin. Researchers used machine learning to analyze EEG recordings from about 7,000 adults and found that an older-than-expected “brain age” was tied to a sharply higher dementia risk. Every additional 10 years of brain aging raised that risk by nearly 40%.

Among American teens, rates of drug and alcohol abuse and mental health issues are holding steady or trending downward, according to data from the new National Survey on Drug Use and Health. Compared to five years ago, teens are using less marijuana, vaping less nicotine, and drinking less alcohol. Fewer teens are reporting symptoms of depression and thoughts of suicide. However, the teens that are struggling often do not get the help they need. Last year, 3.7 million teens dealt with major depression, and two in five did not receive any mental health treatment. And while nearly 2 million teens needed substance use care, four out of five got no treatment for their addiction or drug abuse.

Even mild inflammation during pregnancy led mouse offspring to develop persistent brain overactivity, sensory sensitivity, repetitive behaviors, and increased seizure risk. Remarkably, one dose of rapamycin improved nearly all of these problems within about two hours. The benefits were temporary, but they suggest that adult brain circuits may remain far more adaptable than previously believed.

A massive genetic study has identified nine new genes linked to hyperemesis gravidarum, the most severe form of pregnancy sickness, bringing the total number of known risk genes to ten. The discoveries provide fresh insight into why some women experience debilitating nausea and vomiting during pregnancy while others do not. Several of the newly identified genes are involved in appetite, nausea, metabolism, and brain function, opening the door to more targeted treatments.

A majority of American teens age 13 to 17 get their news daily from social media, which differs sharply from older Americans. Teens are also more likely to rely on influencers and independent content creators rather than national new outlets, while a small number also turn to search engines and AI chatbots to keep up with current events. At the same time, teens are realistic about the potential shortcomings of these information sources. While they often turn to non-traditional news sources, only about 12 percent of teens have a “great deal of confidence” in what they hear from sources like influencers, and only 11 percent feel that way about information from AI sources. Plus, a third of teens say they feel confident they can spot AI content, a higher proportion than adults.

An unexpected study found that young non-smokers with healthier diets had higher rates of lung cancer, raising questions about whether pesticide exposure from conventionally grown produce could play a role. Researchers stress that the findings are preliminary and require further studies before any conclusions can be drawn.

Researchers found that every pregnancy rewires the brain in its own way, with a second pregnancy bringing a different pattern of changes than the first. The discoveries could lead to better ways to recognize and treat maternal mental health challenges, including peripartum depression.

Heavy marijuana smoking may raise the risk of lung cancer and several head and neck cancers, according to growing research, but many important questions remain unanswered. Scientists are still trying to determine how much marijuana use is enough to significantly increase cancer risk. Edibles have not been linked to lung cancer so far, while the long-term effects of vaping marijuana and secondhand marijuana smoke are still being investigated.

A new once-daily weight-loss pill called orforglipron delivered better weight loss and blood sugar improvements than the leading oral semaglutide in a major clinical trial. The tablet could offer a more convenient alternative to injectable drugs like Ozempic and Wegovy because it doesn't require refrigeration or special timing with meals. It's also cheaper to manufacture, which could expand access globally.

A large study found that pregnant women are exposed to dozens of common chemicals, many of which were associated with earlier births and lower birth weights. Researchers also discovered that some replacement chemicals may be just as concerning as the substances they were designed to replace.

Teens who use cannabis may face a substantially greater risk of developing serious mental health conditions, including psychotic and bipolar disorders, according to a study of more than 463,000 adolescents. Researchers found cannabis use often preceded these diagnoses by nearly two years, strengthening concerns about its long-term effects on developing brains.