DRUGS that change the chemistry and structure of the brain could boost the intelligence of people with Down鈥檚 syndrome.
Several compounds have improved memory and learning in a mouse version of the condition, suggesting that its cognitive effects can be changed. Until recently, this idea was unthinkable, says at the Centre for Genomic Regulation in Barcelona, Spain.
Such efforts to improve brain function are controversial, with some activists saying people should be valued as they are. But some families have decided to give their children drugs like Prozac that have not yet been thoroughly tested for Down鈥檚 syndrome. 鈥淢any more studies have to be done first,鈥� says Dierssen.
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Down鈥檚 syndrome arises when a fertilised egg ends up with an extra chromosome. This affects every cell in the baby鈥檚 body and as heart disease and an early susceptibility to dementia.
The IQ of people with the condition also tends to be about 50 points lower than the general average, although there is wide variability. People with Down鈥檚 syndrome seem to have fewer neurons in some brain areas, fewer connections between neurons, and altered neuron behaviour.
In both mice and people, a molecule called NKCC1 seems to be involved. Reducing levels of this compound in neurons taken from Down鈥檚 syndrome mice makes them sprout more connections, Laura Cancedda of the Italian Institute of Technology in Genoa told the conference in Copenhagen, Denmark, last month.
鈥淲e have seen with autism that parents will do anything to enhance their child鈥檚 cognitive ability鈥�
In 2015, her team found that using a drug called bumetanide to block this molecule made Down鈥檚 syndrome mice other mice in memory tests. The drug is already used to treat heart disease, and trials in adults with Down鈥檚 syndrome are set to start towards the end of this year, says Cancedda.
Prozac has also been found to in Down鈥檚 syndrome mice 鈥� perhaps by making extra neurons grow. The drug is a common antidepressant, so some parents have decided to give it to their child on the basis of this early evidence. Women are also choosing to take it while pregnant with a baby that has Down鈥檚 syndrome, says at the University of Texas Southwestern Medical Center in Dallas.
Tamminga has now begun a small placebo-controlled trial of Prozac in pregnant women. However, she has found that many families would rather try Prozac themselves than risk being allocated to the trial鈥檚 placebo group. 鈥淭hose who are potentially interested in doing this are doing it anyway,鈥� she says.
A different compound has produced small positive benefits when tested in people. EGCG, an extract from green tea, reduces the activity of an enzyme that is overproduced in the brains of people with Down鈥檚 syndrome. In July, a placebo-controlled trial in 84 adults in some tests involving memory, reasoning and mental focus. Although changes were modest, over a lifetime they could lead to improved abilities, says at University College London.
鈥淭here鈥檚 a lot of hype. We have seen with autism that parents will do anything to enhance the cognitive ability of their child,鈥� says , a disabled activist and researcher at the University of East Anglia in Norwich, UK. We need more evidence about the safety and effectiveness of potential Down鈥檚 syndrome medication, he says.
Rather than trying to develop drugs, it would be better to change our education and work systems to enable people with Down鈥檚 syndrome to live fuller lives, says Simone Aspis at the UK campaign group .
But Shakespeare says that if such drugs prove to be safe and effective, they could help give people with Down鈥檚 syndrome more independence: 鈥淚鈥檝e no objections to this in principle.鈥�
This article appeared in print under the headline 鈥淒rugs may lift IQ in people with Down鈥檚 syndrome鈥�
