The Observer
09/09/2001
By Jean West
The children’s drug Ritalin has a more potent effect on the brain than cocaine, a study has found.
Using brain
imaging, scientists have found that, in pill form, Ritalin – taken by thousands
of British children and four million in the United States – occupies more of
the neural transporters responsible for the ‘high’ experienced by addicts than
smoked or injected cocaine. The research
may alarm parents whose children have been prescribed Ritalin as a solution to
Attention Deficit Hyperactive Disorder.
The study was
commissioned to understand more about why Ritalin – which has the same
pharmacological profile as cocaine – is effective in calming children and
helping them concentrate, while cocaine produces an intense ‘high’ and is
powerfully addictive. In oral form,
Ritalin did not induce this intense psychological ‘hit’. But Dr Nora Volkow, psychiatrist and imaging
expert at Brookhaven National Laboratory, in Upton, New York, who led the
study, said that injected into the veins as a liquid rather than taken as a
pill, it produces a rush that ‘addicts like very much’. Interviewed in last week’s Journal of the American Medical Association
newsletter, she said: ‘They say it’s like cocaine.’
Even in pill form,
Ritalin blocked far more of the brain transporters that affect mood change and
had a greater potency in the brain than cocaine. Researchers were shocked by this finding. A normal dose administered to children blocked
70 per cent of the dopamine transporters.
‘The data clearly show the notion that Ritalin is a weak stimulant is
completely incorrect,’ said Volkow.
Cocaine is known to block about 50 per cent of these transporters,
leaving the surfeit of dopamine in the system, which is responsible for the hit
addicts crave. But now it is known that
Ritalin blocks 20 per cent more of these auto-receptors.
‘I’ve been almost
obsessed about trying to understand [Ritalin] with imaging,’ said Volkow. ‘As a psychiatrist I sometimes feel
embarrassed [about the lack of knowledge] because this is by far the drug we
prescribe most frequently to children.’
However, it was
still not clear why a drug that has been administered for more than 40 years
was not producing an army of addicted schoolchildren. Volkow and her team concluded that this was
due to the much slower process of oral ingestion. It takes around an hour for Ritalin in pill
form to raise dopamine levels in the brain.
Smoked or injected, cocaine does this in seconds.
Dr Joanna Fowler,
who worked with Volkow on the project, said: ‘All drugs that are abused by
humans release large quantities of dopamine.
But dopamine is also necessary for people to be able to pay attention
and filter out other distractions.’
But opponents of
Ritalin, labelled a ‘wonder drug’ and a chemical ‘cosh’, believe it may be
addictive and has dangerous side-effects.
Moreover, many believe ADHD is a fraudulent title for a non-existent
condition once put down to the exuberance of youth. Professor Steve Baldwin, a child psychologist
from
Mandy Smith of
Banff in
Janice Hill, of
the Overload Support Network, a charity for parents of children with
behavioural problems, said: ‘Now we have thousands of children in
A spokeswoman for
Novartis, which makes Ritalin, said: ‘Ritalin is available as tablets
only. It should only be initially
prescribed by a doctor who is a specialist in child behavioural disorders and
should always be used and monitored under strict medical supervision.’