SEEKING THE ROOTS TO SUICIDE

Tzigane

Victims of child abuse might experience biochemical changes to their brains that leave them more vulnerable to suicidal urges as adults.

A McGill research team—including psychiatry professor MICHAEL MEANEY, pharmacology and therapeutics professor MOSHE SZYF, postdoctoral fellow PATRICK MCGOWAN and Dr. GUSTAVO TURECKI, PhD'99, director of the McGill Group for Suicide Studies—compared the brains of men who had taken their own lives (and who had all experienced abuse as children) with those of accident victims who had grown up under normal circumstances. The researchers, who published their findings in the journal Public Library of Science One, noted differences between the two groups in their epigenetic marking. While DNA is inherited and remains fixed throughout life, the functioning of its genes is influenced by a chemical coating. These epigenetic marks, which appear to be sensitive to environmental factors early in life, program the DNA to express certain genes at the appropriate time and place.

In examining the brains of the suicide victims, the McGill team found evidence of epigenetic differences in the genes that produce rRNA, which is a basic structure in the protein-producing machinery. Protein synthesis is essential for learning, memory and the building of new connections in the brain. It is also linked to decision-making.

"It's possible the changes in epigenetic markers were caused by the exposure to childhood abuse," says Szyf. "The big remaining questions are whether scientists could detect similar changes in blood DNA—which could lead to diagnostic tests—and whether we could design interventions to erase these differences in epigenetic markings."

CYNTHIA LEE

SMART DINING

Bernie Mireault

Want your baby to be bright? Then it might be a good idea to breastfeed instead of using formula.

According to the largest randomized study of its kind ever put together, prolonged breastfeeding seems to offer a boost to kids' IQ scores and to their classroom performance as they get older.

"Our study provides the strongest evidence to date that prolonged and exclusive breastfeeding makes kids smarter," says McGill pediatrics and epidemiology and biostatistics professor MICHAEL KRAMER, who headed the research project.

More than 17,000 infants were monitored in Belarusian hospitals and clinics for the study, and close to 14,000 of them were followed up when they were six and a half years old. Half the mothers participating in the study were encouraged to breastfeed their little ones exclusively for a prolonged period.

As the children got older, their cognitive ability was assessed by IQ tests administered by pediatricians and by their teachers' ratings of their academic performance in reading, writing, mathematics and other subjects. Both sets of measures were significantly higher in the group that was exclusively breastfed. They scored, on average, 7.5 points higher in verbal intelligence, and 5.9 points higher in overall intelligence.

"This is not the difference between mental retardation and a genius," Kramer told the CBC. "But if you consider for the whole population shifting the mean [IQ score] up three or four points, that means fewer difficulties for kids at the lower end and more Einsteins and Mozarts at the high end." The study was published in Archives of General Psychiatry.

CYNTHIA LEE