Pubdate: Fri, 20 Nov 2015
Source: New Zealand Herald (New Zealand)
Copyright: 2015 New Zealand Herald
Author: Martin Johnston
Page: A23


Visual test shows better scores in children exposed to drug in

Smoking cannabis during pregnancy produces infants who score better on
one measure of brain development, according to a study of New Zealand

The researchers say their test outcome cannot be construed as maternal
marijuana use being good for babies' brains.

Drinking alcohol, however, led to worse scores - and when both drugs
were used, they cancelled each other out.

But the optometry and psychology researchers who did the study warn
that women should not self-medicate on the strength of their findings
because cannabis use in pregnancy is also known to lead to poor
outcomes on other measures of brain development,

In the study, 165 children aged 41⁄2 watched multiple moving
dots on a computer screen and were asked to state the main direction
in which they were moving. It is a measure of visual discrimination in
the brain called global motion perception.

Arijit Chakraborty of the University of Auckland likened the test to
identifying a single moving car at a busy intersection.

He and his co-researchers found the scores were markedly better in
those whose mothers used cannabis in pregnancy than in offspring of
those who didn't use it in pregnancy. The more frequently the mothers
smoked and the larger the quantities, the greater the benefit.

Children of mothers who drank in pregnancy performed worse than those
whose mothers did not drink, although none of the children in the
study had been diagnosed with fetal alcohol syndrome. The more the
mothers drank, the greater the visual impairment. Nicotine and
methamphetamine had no effect and none of the four drugs affected
other visual measures including visual acuity.

The researchers' paper, published yesterday in the journal Scientific
Reports, says that if the cancelling-out they found with alcohol and
cannabis can be repeated, this could provide a basis for future
research on "new ways to prevent or ameliorate" the ill effects of
prenatal drug exposure.

But Mr Chakraborty says women should await the results of scientific
study on this rather than undertaking their own experiments at home.

"One improvement in one particular neuro-developmental domain does not
suggest holistically the brain is performing better. We would
recommend the mothers to stop drinking in the first place instead of
trying marijuana."

The researchers say that although prenatal cannabis exposure has not
been studied widely, "detrimental effects have been reported for motor
and cognitive development. Therefore our results cannot be
extrapolated beyond global motion perception or interpreted as
marijuana having beneficial effects on fetal development.

"Previous studies have reported that prenatal exposure to heavy
marijuana use impairs performance on a range of . . . tests of
attention, memory, and executive function that involve a visual
- ---
MAP posted-by: Matt