Adolescents who frequently use smartphones and other digital devices are more likely to develop symptoms of attention-deficit hyperactivity disorder (ADHD), reveals a research study published in the Journal of the American Medical Association (July). The study focused on the impact of digital diversions, including social media, streaming video, text messaging, music downloads and online chatrooms, among others, on the mental health and well-being of adolescents.
“We can say with confidence that teens exposed to higher levels of digital media are significantly more likely to develop ADHD symptoms in the future,” says Adam Leventhal, professor of preventive medicine and psychology and director of the University of Southern California’s Keck School of Medicine.

The research team analysed data derived from 2,587 teenagers who were asked to report how frequently they used 14 popular digital media platforms over a period of two years.

Sex of baby influences pregnancy complications

A study published in the journal JCI Insight (July) has found that the placentas of male or female foetuses control the level of molecules known as metabolites, which explains why risks of disease in pregnancy vary depending on the infant’s biological sex.

The study analysed data relating to 4,000 first-time mothers and examined samples of placenta and maternal blood. Female placentas had much higher levels of the enzyme that makes spermine, thus increasing levels of metabolite which is associated with pre-eclampsia risk, whereas placental cells of males were found to be more susceptible to the toxic effects of a drug that blocked spermine production, which may lead to poor foetal growth.

“These differences alter the composition of the mother’s blood and may enhance or diminish the risk of pregnancy complications. A better understanding of these differences could lead to new predictive tests and possibly even new approaches to reducing the risk of poor pregnancy outcomes,” says lead author, Gordon Smith, professor at the NIHR Cambridge Comprehensive Biomedical Research Centre of the University of Cambridge, UK.

Early childhood memories are fictional

Any memories you may have of taking your first steps or uttering your first words are likely to be fictional, says a study published in the Psychological Science Journal (July). The largest ever survey on the subject of first memories has concluded it is improbable that humans remember anything before three-and-a-half years of age. The study conducted by City, University of London, the University of Bradford and Nottingham Trent University found that 38.6 percent of 6,641 people surveyed claimed to have memories from two or younger. In that group 893 respondents claimed memories from age one or younger. These early memories “related to infancy” — many revolving around prams — are often the result of memory mixed with imagination, says this path-breaking study.
“As many of these memories dated before the age of two and younger, the authors suggest that these fictional memories are based on remembered fragments of early experience — such as a pram, family relationships, and sad feelings — and some facts or knowledge about their own infancy or childhood which may have been derived from photographs or family conversations,” says a press release issued by the researchers.

Binge drinking in adolescence affects memory

Binge drinking impairs working memory in the adolescent brain, says a study published in the Journal of Neuroscience (July). Researchers at the Columbia University Irving Medical Center studied mice given access to alcohol every other day during a period in their development equivalent to human adolescence.

The study found that the most striking changes appeared in neurons within the mouse equivalent of the human prefrontal cortex (PFC), which suppresses inappropriate responses and maintains working memory and attention. “These findings may help explain why adolescent binge drinkers have memory problems but they also suggest ways to intervene. Targeting these channels may restore normal patterns of activity in the PFC and improve working memory,” says Neil Harrison, professor of anesthesiology and pharmacology at Columbia University’s Vagelos College of Physicians and Surgeons.