boston.com News your connection to The Boston Globe

Discoveries

-- Researchers using the Hubble Space Telescope announced last week that they have surveyed 50,000 galaxies, dating as far back as 8 billion years, providing "by far the most detailed picture of galaxy evolution to date," said Anton Koekemoer of the Space Telescope Science Institute in Maryland. (HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS)

Teen brains react differently to stress than adult ones

NEUROSCIENCE
A brain chemical that reduces anxiety in adults has the opposite effect on adolescents, a new study finds, perhaps explaining why many teenagers are so touchy. Neurosteroids are produced mostly by the brain under stressful conditions and boost the activity of special brain receptors called GABA receptors that work to calm excited nerve cells and reduce anxiety. However, using cell cultures maintained under conditions similar to those during puberty in mice and humans, a group of researchers led by Sheryl S. Smith of SUNY Downstate Medical Center found that the neurosteroid THP, or tetrahydropregnanalone, actually inhibits a rare type of GABA receptor. This rare receptor increases dramatically at puberty in a part of the brain that generates emotion, and its inhibition could be responsible for an increased level of anxiety in adolescents under stress.

BOTTOM LINE: "We now have a biological basis for why teenagers are more irritable, angry, and rebellious in response to stress," said Smith.

CAUTIONS: The study dealt with just female mice. Researchers don't know if the same effect will be observed in male mice, not to mention teenagers.

WHAT'S NEXT: Smith is now experimenting with mice, with the ultimate goal of developing medications that will prevent this abnormal effect.

WHERE TO FIND IT: Nature Neuroscience, March 11

SENA DESAI GOPAL

PSYCHOLOGY

Mental torture is just as damaging as physical torture


The mental health impact of psychological torture is just as damaging as physical torture, a study on 279 torture survivors in former Yugoslavia found. The ill treatment often labeled as another form of interrogation or "torture lite" -- including psychological manipulation, humiliation, threats of rape, isolation, sham executions, and sleep deprivation -- caused just as much distress and feeling of uncontrollability as torture that inflicted physical pain. What's more, victims who reported feeling more distressed and especially more helpless from either form of torture were more likely to develop post-traumatic stress disorder and depression later on. The outcome "depends on whether or not the person being tortured is prepared to be tortured," -- for example an insurgent versus a civilian, explained Dr. Steven Miles, a professor at the University of Minnesota Center for Bioethics. The study, which follows reports of human rights abuses by the American military in Iraq, Afghanistan, and Guantanamo Bay, "undermines the very distinction that's built into government policy that there's a difference between torture and inhumane and degrading treatment" at these sites, says Miles. The current definition of torture by the US Departments of Justice and Defense does not include non-physical torture, according to the paper.

BOTTOM LINE: "This study is a sobering reminder that torture and mistreatment -- either physical or psychological -- can have devastating health consequences," Dr. Allen Keller, associate professor of medicine at NYU School of Medicine and director of the Bellevue/NYU Program for Survivors of Torture, wrote in an e-mail.

CAUTIONS: The researchers were not able to parse the impact of individual torture mechanisms since most victims were subjected to multiple forms.

WHAT'S NEXT: Therapies that help torture survivors gain a sense of control over their experiences may help prevent and treat their post-traumatic stress disorder and depression, says the study's lead author, Metin Basoglu of the Institute of Psychiatry at King's College in London. He and colleagues have successfully tested such an approach in earthquake survivors using an earthquake simulator.

WHERE TO FIND IT: Archives of General Psychiatry, March 2007

ISHANI GANGULI

SEARCH THE ARCHIVES