``As a psychiatrist, sometimes I feel embarrassed [about the lack of knowledge] because this is, by far, the drug we prescribe most frequently to children,'' said Nora Volkow, MD, of Brookhaven National Laboratory. But the answer provided by PET (positron emission tomography) could be still more embarrassing. Ritalin blocks dopamine reuptake in the brain, thus increasing the concentration of this neurotransmitter, which stimulates reward and motivation circuits-like cocaine.
The 2 to 4 million children on Ritalin, however, do not appear to be high. Pharmacologists thought that might be explained by lesser potency. But as Volkow was ``shocked'' to discover, Ritalin is actually more potent than cocaine. Its addictive potential is assumed to be less because it takes about an hour to raise dopamine levels-at least when taken orally-whereas injected or snorted cocaine raises the levels within seconds.
Other work suggests that persons with ADHD have many more dopamine transporters than normal, so that the dopamine they produce is ``vacuumed up'' more quickly. Thus, they receive weaker dopamine signals and presumably experience less reward from interesting activities. Ritalin might be returning the signal to a more ``normal'' level.
Cocaine use leads to adaptations in brain physiology that may decrease activity in reward pathways, which helps explain the depression or anhedonia that occurs on withdrawal. Besides mediating pleasure, dopaminergic neurons regulate cerebral blood flow. Extracellular dopamine causes vasospasm. Poor blood flow to certain areas can persist even after 6 months of abstinence, resulting in neuronal death. The risk of stroke is increased, and blood vessels elsewhere in the body may also be damaged, leading to kidney failure, intestinal ischemia, amputations, and heart attack. After adjusting for other risk factors, frequent cocaine users have about a seven-fold higher risk of having a nonfatal heart attack.
What are the long-term risks of Ritalin? ``The long-term dopamine effects of taking methylphenidate for years, as many do, are another unknown.'' One of only two long-term studies shows more drug addiction in ADHD patients on Ritalin, and the other one shows the opposite effect. It is not clear whether Ritalin lowers the seizure threshold or induces tics. In one study, 6 of 98 children treated for ADHD with stimulants developed psychotic symptoms (Can J Psychiatry 1999;44:811-813). There is one case report of a 14-year-old who experienced a fatal cardiac arrest while skateboarding, after 10 years of Ritalin treatment. Autopsy showed scarring in small blood vessels (WorldNetDaily 5/7/00).
One 8-year-old suffered a stroke. Family history and risk factors other than Ritalin use were absent. ``Stroke is a well-documented complication of amphetamine abuse,'' the authors commented. ``Methylphenidate [is] chemically and pharmacologically similar to amphetamine.... The possibility of vasculitis connected to methylphenidate should not be surprising'' (J Child Neurol 2000;15:265-267).
There is increasing evidence that Ritalin is being diverted to illicit use by snorting or injection, with some fatalities, at least one from intranasal use (J Forensic Sci 1999;44:220-221).
Despite the fact that little is known about the effects of psychotropic drugs, including Ritalin, in small children, the number of 2 to 4 year olds on such drugs increased from 100,000 in 1991 to 150,000 in 1995 (WorldNetDaily 2/27/00). Ritalin is by far the most common drug, and at some study sites, prescriptions increased by a factor of three in this age group (JAMA 2000;283:1059-1060).
Could Ritalin affect the development of the toddler's brain? ``[U]ntil now, possible effects of this treatment on brain development and maturation of monoaminergic systems have not been investigated systematically,'' write the authors of a study of methylphenidate in prepubertal and postpubertal rats. They found that the density of dopamine transporters in the striatum of the brain was reduced significantly after early administration of the drug. The decline reached almost 50% at adulthood, long after treatment stopped (J Child Adolescent Psychopharmacology 2001;11:15-24).
Interestingly, both cocaine-dependent individuals and children treated with stimulants are more likely than average to smoke cigarettes. Nicotine also increases dopaminergic transmission, though by a different mechanism (Synapse 2000;38:432-437), and of course has some similar effects on the blood vessels. (Cocaine addicts can't tell the difference between intravenous nicotine and cocaine.) It is possible that smokers have for a long time been treating themselves for depression or excitability; it is stated that quick puffs stimulate and long drags calm. Many have claimed that smoking, like Ritalin, increases dexterity and alertness and improves driving ability. Congress has even exempted airline pilots from the ban on smoking on domestic flights (www.vdare.com/pb/smoking.htm).
We can be reassured that lawmakers, lawyers, and bureaucrats are protecting us against second-hand smoke and mass seduction by wicked tobacco companies. And hip-looking, ethnically diverse young people assure the television audience that they have gotten their parents' message-about tobacco.
On the other hand, failure to use Ritalin could subject a physician to a threat of delicensure or a parent to loss of child custody (AAPS News 1/01). The Arizona legislature killed a bill specifying that ``a parent or guardian is not committing abuse or neglect for refusing to place a child on psychiatric medications or to question the use of that medication and that that action is not, of itself, reason for the Child Protective Services (CPS), a peace officer or the court to take any action regarding that parent's custody.''
The ``encore'' replay of the 19th annual DDP meeting was so successful that host Bob Heckler has been devoting 2 hours each Friday of drive-time programming to follow-up interviews. The program airs 7 to 9 a.m. Eastern time on WXBH 1190 and will be simulcast live on the Internet to the rest of the world (www.wxbhradio.com). Past interviews have featured Willie Soon, John Toman, and Sallie Baliunas. Dr. Bernard Cohen will be heard on September 14, J. Gordon Edwards on September 21, Jane Orient on September 28, and Sharon Packer and Paul Seyfried on October 5.
Other scientists associated with DDP will also be considered. If you'd like to be interviewed, call Mr. Heckler at (518) 234-3400, send e-mail to wxbh@wxbh.zzn.com, or postal mail to PO Box 608, Cobleskill, NY 12043.
Mr. Heckler writes: ``We really do need more members to sign on for this opportunity. The listening audience loves it. The station gets many calls afterward, but none during the show. They all say they absolutely enjoy hearing true scientists and don't want to interrupt.''
DDP, 1601 N. Tucson Blvd. Suite 9, Tucson, AZ 85716, (520)325-2680, www.oism.org/ddp.