TIME Research

Why Smoking Pot Brings On the ‘Munchies’

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Marijuana can shake up the chemicals in your brain

Wherever marijuana is smoked, the consumption of snacks usually follows — and a new study suggests that’s because pot causes changes in brain circuitry that make you hungry.

Pot heads and scientists alike have long known that marijuana can make a person crave food, a phenomena known colloquially as the munchies. But the evidence is still cloudy when it comes to why this happens. So a team of Yale researchers set off to figure it out.

In a new study published in the journal Nature, the researchers discovered that cannabinoids from marijuana actually interfere with signaling in the brain that causes the body to feel hungry when it should be feeling full. To do so, they looked at the brains of high mice.

The researchers observed that the neurons in the mice brains that make them feel sated, called POMCs, were activated in those who were given a chemical to mimic marijuana in the brain. At first, it didn’t make any sense. If the neuron in the brain that inhibits hunger is activated, then shouldn’t the mice be much less hungry? Not hungrier?

What the team discovered was that the cannabinoids interfere with the chemical POMCs’ release — so that when the mice were “sober,” the neurons released a satiety chemical. But when the mice were “high,” their neurons released a chemical that spurs appetite.

“It’s like pressing a car’s brakes and accelerating instead,” said study author Tamas Horvath in a statement. “We were surprised to find that the neurons we thought were responsible for shutting down eating, were suddenly being activated and promoting hunger, even when you are full. It fools the brain’s central feeding system.”

The new findings join the many working theories looking at why marijuana causes hunger. A study from last February, for example, suggests that the THC in marijuana activates smell receptors which causes hunger. The new results are still preliminary and require further research. For now, the jury is still out.

Read next: This Event Will Teach Businesspeople How to Buy Pot

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TIME public health

People Who Sext Are More Likely to Text While Driving

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'Technological deviance' may be the reason why

More than a quarter of American adults admit to texting while driving, but not everyone is equally likely to engage in the dangerous practice, finds a new study published in the journal Cyberpsychology, Behavior, and Social Networking. People who text and drive are more likely to be white than nonwhite, men than women and sexters than the sext-abstinent.

“In modern social life, we are tethered to our devices,” says study author Steven Seiler, assistant professor of sociology at Tennessee Tech University. “When we’re driving, we’re simply taking the norms that we have in other areas of life.”

The study evaluated survey data from more than 2,200 American adults and found that more than 27% of drivers admitted to texting while driving. The practice seemed to be fueled by a sense of constant connection to others. What the authors call “technological deviance,” a disregard for social norms around technology, may help explain why sexting was an associated behavior.

Read More: How Your Cell Phone Distracts You Even When You’re Not Using It

Even though a majority of states ban texting while driving, Seiler says he is skeptical that such laws are the most effective way to stop the practice. New Jersey, a state that keeps extensive records on texting-while-driving enforcement, enacted strict laws to ban the practice more than five years ago, but hasn’t seen a decline since, Seiler says.

“When there’s laws prohibiting mobile phones, rather than keeping the mobile phones near their face, they’ll keep it in their lap,” he says. “The change has to occur on a cultural level, not simply stricter laws.”

Much like state laws, simple restrictions aren’t likely to change culture. Students who attend a school that bans mobile phones from the classroom are more likely to engage in texting while driving, Seiler says he found in an forthcoming study. “They’re catching up on that time lost,” he says. “This goes back to how integrated cell phones are with our relationships.”

To truly eradicate the practice, Seiler says the dangers of texting while driving need to be ingrained in a child early in their socialization. Parents need to monitor their children’s texting, and texting while driving should have consequences, he says.

Traffic safety campaigns should try to spread the message in every way possible, much like the seatbelt campaign of the 1990s, he says. In the United States in 2012, more than 3,000 people were killed in distracted driving accidents, which include talking on the phone and texting while driving.

Read more: Why People Text And Drive Even When They Know It’s Dangerous

TIME HIV/AIDS

Scientists Find a Way to Block HIV from Infecting Healthy Cells

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Getty Images HIV viruses infecting a human immune cell

Researchers overcome a major hurdle in developing the ultimate protection against HIV

Reporting in the journal Nature, scientists describe a new way to potentially block HIV from infiltrating healthy cells. Such interference is key to protecting people from HIV infection, but most efforts so far haven’t been successful.

This time, however, may be different. Michael Farzan, professor of infectious diseases at Scripps Research Institute, and his team used a gene therapy technique to introduce a specific HIV disruptor that acted like gum on HIV’s keys. Once stuck on the virus’s surface, the peptide complex prevents HIV from slipping into the molecular locks on healthy cells. Because the gum isn’t picky about which HIV strain it sticks to—as long as it’s HIV—the strategy works against all of the strains Farzan’s group tested in the lab, including both HIV-1 and HIV-2 versions that transmit among people, as well as simian versions that infect monkeys. In lab dishes containing the virus and human and animal cells, the disruptor managed to neutralize 100% of the virus, meaning it protected the cells from getting infected at all.

MORE: The End of AIDS

The strategy is based on what HIV experts know about how the virus infects healthy cells. HIV looks for a protein, or receptor on immune cells called CD4, which serves as the lock, and uses a specially designed portion of its own viral coat made up of three proteins as the key. Once HIV finds its target and the match is made, the virus changes its shape to better slip inside the healthy cell, where it takes over the cell’s machinery and churns out more copies of itself. Farzan’s gum, called eCD4-Ig, not only seeks out these parts of the key and renders them useless, but by glomming onto the key, also causes the virus to morph prematurely in search of its lock. Once in lock-finding mode, the virus can’t return to its previous state and therefore is no longer infectious.

The encouraging results suggest that eCD4-Ig could provide long-term protection against HIV infection, like a vaccine; in four monkeys treated with gene therapy to receive eCD4-Ig, none became infected with HIV even after several attempts to infect them with the virus. The protection also seems to be long-lasting. So far, the treated monkeys have survived more than a year despite being exposed to HIV, while untreated control monkeys have died after getting infected.

MORE: This Contraceptive Is Linked to a Higher Risk of HIV

The strategy, while promising, is still many steps away from being tested in people. Farzan used a cold virus to introduce the eCD4-Ig complex directly into the muscle of the animals, and it’s not clear whether this will be best strategy for people. Previous gene therapy methods have led to safety issues, and concerns have been raised about controlling where and how much of the introduced material gets deposited in the body. It may also be possible to give the peptide as an injection every few years to maintain its anti-HIV effect.

MORE: HIV Treatment Works, Says CDC

Farzan anticipates that if proven safe, the strategy could help both infected patients keep levels of HIV down, as well as protect uninfected, high-risk individuals from getting infected. But many more tests will need to be done before we might see those results. Four monkeys can provide valuable information, but can’t answer questions about safety and efficacy with any confidence. “Things change when we get to humans and when we get to larger numbers,” he says. “But the data in monkeys are as encouraging as one could hope.”

TIME Innovation

Five Best Ideas of the Day: February 17

The Aspen Institute is an educational and policy studies organization based in Washington, D.C.

1. Is the Taliban’s fracturing a sign of its demise or a possible turn to a more lethal strategy?

By Sundarsan Raghavan in the Washington Post

2. To fight cybercrime, President Obama needs Silicon Valley.

By Katie Benner in Bloomberg View

3. The FDA needs updated systems to review drugs — made from our own cells — that target cancer and more.

By Peter W. Huber in City Journal

4. Our high incarceration rate no longer reduces crime.

By Lauren-Brooke Eisen in USA Today

5. Better than an action movie: Catch a college lecture on your next commercial flight.

By Kim Clark in Money

The Aspen Institute is an educational and policy studies organization based in Washington, D.C.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME Addiction

Plain Cigarette Packs May Deter Smokers, Studies Show

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Largely based on findings in Australia, which removed branding from tobacco packaging two years ago

Tobacco packaging without labels or branding may keep new smokers away and prevent habitual smokers from lighting up regularly, a new series of studies finds.

According to the studies, published in the journal Addiction, there is growing evidence that plain packages of cigarettes and other tobacco products reduce smoking rates and reduce outdoor smoking. The findings are largely based on evidence noted in Australia, where the government removed labels from cigarette packages and added graphic health warnings to packs two years ago.

The studies also show that by removing the branding, young experimental smokers focus more on the health warnings on the package — though it found the impact on daily young smokers is minimal.

“Even if standardized packaging had no effect at all on current smokers and only stopped 1 in 20 young people from being lured into smoking it would save about 2,000 lives each year,” Addiction editor-in-chief Professor Robert West said in a statement.

Addiction published the series just months before the U.K. Parliament votes on standardizing tobacco product packaging, following in the footsteps of Australia. The government is already facing fierce backlash from tobacco companies in response to the law, Reuters reports.

John Oliver brought up Australia’s law in his segment on tobacco marketing on this week’s Last Week Tonight:

Read next: This Is The Easiest Way to Get Better Sleep

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TIME Research

A Quarter of New Psychotic Disorders Linked to ‘Skunk’ Cannabis, Study Says

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Daily users of high-potency marijuana are five times more likely to suffer psychosis than those who never touch it

One in four new cases of psychotic disorders could be directly linked to the use of high-potency “skunk-like” cannabis, a new study has found.

Researchers from King’s College London found smokers of super-strength cannabis, colloquially known as skunk, were three times as likely to develop symptoms of a psychosis than those who don’t use the drug, the BBC reports.

That risk increases to five times as high if the user smokes skunk on a daily basis.

“The results show that psychosis risk in cannabis users depends on both the frequency of use and cannabis potency,” said Dr. Marta Di Forti, lead author of the study.

However, the team found that milder varieties of cannabis such as hashish did not increase the risk of psychotic illness.

Psychosis refers to hallucinations or delusions that can be found in certain psychiatric conditions such as schizophrenia or bipolar disorder.

Read next: Driving While Stoned Is Much Safer Than Driving Drunk, Says a New Study

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TIME Research

Scientists Say Aggressive New HIV Strain Discovered in Cuba

Reports of people in Cuba infected by new strain developing AIDS in less than three years

A recently-discovered form of HIV in Cuba has been found to progress into AIDS some three times faster than the most common strains of the virus, according to a recent study.

The study, conducted by researchers from the University of Leuven in Belgium, followed several reports of HIV-infected people in Cuba developing AIDS in less than three years, far faster than the usual 10 years it typically takes. All patients infected with CRF19, a recently-discovered strain of the HIV virus, had higher levels of it in their body.

They were also more likely to have developed AIDS within three years, the study published in the journal EBioMedicine found. The researchers, who looked at 95 patients at various stages of infection, concluded that the strain must be “particularly fit.”

Approximately 35 million people worldwide are living with HIV or AIDS, and nearly 40 million have died of the disease since the 1980s. Drugs exist to keep the worst effects of the disease at bay, but this new strand threatens to take a toll on patients before they realize they need treatment.

TIME Research

Most Women Experience Hot Flashes for Over 7 Years, Study Finds

Symptoms of the menopause last longer than previously thought

Hot flashes, night sweats and other symptoms of menopause typically affect women much longer than previously thought, a median of 7.4 years, according to a new study.

The study, published in JAMA Internal Medicine, looked at a group of nearly 1,500 women with frequent symptoms of the onset of menopause and found significant variations in duration of menopausal vasomotor symptoms (VMS) between ethnic groups.

African-American women experience symptoms for a median of 10.1 years, more than any other ethnic group. On average, Chinese and Japanese women experienced the symptoms for the shortest duration—5.4 and 4.8 years, respectively.

Women who experienced hot flashes and night sweats at a younger age tended to have them last longer, the study found, as did women with less education and greater levels of stress.

Read More: Do Married People Really Live Longer?

“These findings can help health care professionals counsel patients about expectations regarding VMS and assist women in making treatment decisions based on the probability of their VMS persisting,” said the study, which notes that 80% of women experience such symptoms.

The study challenges the long-held notion that these experiences “minimally affect women’s health or quality of life and can be readily addressed by short-term approaches,” according to a commentary that accompanies the study.

TIME Research

This Is The Easiest Way to Get Better Sleep

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A new study suggests a simple and inexpensive fix for better sleep

Half of people over age 55 have a sleep problem, but a new study suggests meditating can improve sleep in those who can’t seem to get enough.

In the study, published in the journal JAMA Internal Medicine, researchers looked at 49 men and women around age 66 who were experiencing poor sleep but didn’t have a diagnosed sleep disorder. About half of them enrolled in a standard sleep hygiene education program, and the other half learned mindful awareness practices.

For six weeks, the mindful group spent two hours a week learning a variety of mindfulness and meditation practices, including mindful sitting, eating, movement and meditation. They were asked to practice what they learned at home—but throughout the program, the group never discussed sleep.

“A lot of individuals who are undergoing sleep problems don’t want to talk about their sleep anymore. It just further exacerbates their issue,” says study author David S. Black of the University of Southern California. “I wanted to look at a program where you wouldn’t have to talk about sleep and it would indirectly remediate some of those problems that go along with sleep, like worrying about it.”

At the end of the sessions, the researchers measured everyone’s sleep quality and found that the people learning mindfulness scored higher in better sleep than the other group. They also had improvement in areas like depression, insomnia symptoms and fatigue. The two groups had similar results for anxiety and stress.

The researchers speculate that mindfulness meditation improves nervous system and cognitive system processes that relate to arousal and stress. “Before going to bed, people who can’t sleep worry a lot, and they start ruminating about not being able to sleep,” says Black. “Through mindfulness practice, people learn how to observe thoughts without having to elaborate. It allows people be present without further interpretation of their symptoms.”

Another possibility is that by curbing mood disturbances, meditation can lessen anxiety and let people relax more. Mindfulness might also simply make people think they’re getting higher quality sleep.

The findings are still preliminary, and while they’re not yet robust enough to make clinical recommendations, Black says he envisions mindfulness as a simple, inexpensive intervention for people who don’t have serious sleep problems, like those enrolled in the study. “This trial was intended for the majority of older adults who face sleep problems but do not have a clinical diagnosis of insomnia,” he says. “It opens it up to a broader audience.”

TIME Research

This Is What’s Keeping Teens From Getting Enough Sleep

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STUDIO BOX—Getty Images

The biggest factor keeping teens up at night isn't technology

Up to a third of teens in the U.S. don’t get enough sleep each night, and the loss of shut-eye negatively impacts their grades, mental well-being and physical health. Biologically, adolescents need fewer hours of slumber than kids — but there’s a bigger reason for teens’ sleep loss, according to a new study in the journal Pediatrics.

MORE: The Power of Sleep

Katherine Keyes, an assistant professor of epidemiology at Columbia University, looked at survey data from more than 270,000 eighth-, 10th- and 12th-grade students at 130 public and private schools across the country, gathered between 1991 and 2010. Each student was asked two questions about his or her sleep habits: how often they slept for at least seven hours a night, and how often they slept less than they should.

MORE: School Should Start Later So Teens Can Sleep, Urge Doctors

She found that over the 20-year study period, adolescents got less and less sleep. Part of that had to do with the fact that biologically, teens sleep less the older they get, but Keyes and her team also teased apart a period effect — meaning there were forces affecting all the students, at every age, that contributed to their sleeping fewer hours. This led to a marked drop in the average number of adolescents reporting at least seven hours of sleep nightly between 1991–1995 and 1996–2000.

That surprised Keyes, who expected to find sharper declines in sleep in more recent years with the proliferation of cell phones, tablets and social media. “I thought we would see decreases in sleep in more recent years, because so much has been written about teens being at risk with technologies that adversely affect the sleep health of this population,” she says. “But that’s not what we found.”

MORE: Here’s How Much Experts Think You Should Sleep Every Night

Instead, the rises in the mid-1990s corresponded with another widespread trend affecting most teens — the growth of childhood obesity. Obesity has been tied to health disturbances including sleep changes like sleep apnea, and “the decreases in sleep particularly in the 1990s across all ages corresponds to a time period when we also saw increases in pediatric obesity across all ages,” says Keyes. Since then, the sleep patterns haven’t worsened, but they haven’t improved either, which is concerning given the impact that long-term sleep disturbances can have on overall health.

Keyes also uncovered another worrying trend. Students in lower-income families and those belonging to racial and ethnic minorities were more likely to report getting fewer than seven hours of sleep regularly than white teens in higher-income households. But they also said they were getting enough sleep, revealing a failure of public-health messages to adequately inform all adolescent groups about how much sleep they need: about nine hours a night.

“When we first started looking at that data, I kept saying it had to be wrong,” says Keyes. “We were seeing completely opposite patterns. So our results show that health literacy around sleep are not only critical but that those messages are not adapted universally, especially not among higher-risk groups.”

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