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CMAJ - March 21, 2000JAMC - le 21 mars 2000

Ritalin use in BC

CMAJ 2000;162:753-4

The letter from 3 employees of the BC Ministry of Health calling into question a series of newspaper articles I wrote on rates of methylphenidate use in BC is misleading and conveys a false impression of the series by making a direct comparison between 2 entirely different sets of data.1 I wish to make the following corrections.

The ministry staff challenged as "untrue" the claim made in my articles that "children in some parts of British Columbia were being prescribed methylphenidate (Ritalin) at the highest known rate in North America." This is inaccurate and misleading. The government researchers reached this conclusion by mixing statistical apples and oranges.

First, in their Freedom of Information request to PharmaNet the ministry employees requested prescribing data for a different time frame than that used by The Vancouver Province. This explains why their 12-month total varied from mine by about 200 children.

Second, I clearly stated that my conclusions were based on a survey of prescribing rates in 39 of BC's biggest communities. It is well known that city kids are more likely than rural kids to be diagnosed and treated for attention deficit disorder. They have more access to doctors. But the ministry employees took a much broader survey approach in their Freedom of Information request. Instead of looking at the same data for the specific communities used by The Province, the researchers reviewed prescribing data by "region," which would include many largely rural districts. It is not surprising that direct comparisons found lower rates in these "regions" than in urban communities. I reject as meaningless the claim that "variation in use of the drug across regions was also much smaller than reported by the newspaper." I didn't report by region.

Third, a key point in my series on methylphenidate use is that boys in certain age groups are prescribed stimulants at a much higher rate than any other group in society, including girls of the same or any other age. Even when compared with girls in the same age group, up to 6 times as many boys were on stimulant medications. I published detailed graphs demonstrating the differences between boys and girls in each of the 39 communities. But the ministry researchers blended data for boys and girls and made a direct comparison with my findings for boys alone, which is meaningless.

Fourth, I found marked differences in prescribing rates among boys in different age groups. After carefully analyzing the data for the 39 communities I found that the highest prescribing rates were for boys aged 8 to 13 years. The ministry employees studied a different age group; they looked at combined statistics for boys and girls aged 10 to 14 years, a group who in the communities I studied were prescribed methylphenidate at a lower rate than the 8- to 13-year-old group.

The ministry staff then averaged rates for the entire age group, rolling in boys and girls to the mix. It is not surprising that they were again able to report lower rates of prescribing than those reported for children of a specific age and sex.

Finally, the writers of the letter question my use of Statistics Canada data from the 1996 census for each of the communities involved. These were the most recent population figures available for all communities. I stated very clearly in my lead article that "population figures were obtained from the 1996 Statistics Canada census, so percentages may vary."2 But I went a step further before publishing my results. I checked more recent BC government population statistics available for some of the communities and found that populations had either remained stable or decreased in the smaller communities with the highest rates of use.

I made the case for the highest confirmed rates in part because the PharmaNet base in BC allows a unique view of how drugs are prescribed. I have been unable to find another jurisdiction with such extensive public access to prescribing practices. Interviews with experts from across North America supported my view that no other jurisdiction has yet confirmed such high prescribing rates. I found rates as high as 1 in 4 boys in some communities. In 1 community I found that 9 of 30 boys aged 10 years received methylphenidate over the 12-month period. (I pointed out the small sample size.)

The BC Ministry of Health said at the time of my first series of articles that it would investigate methylphenidate use in BC. I hope that this dismissive and misleading piece of work by ministry staff does not represent the sum total of that effort.

I stand by my statement that children in some BC communities are being prescribed methylphenidate at the highest confirmed rates in North America. I see nothing to shake that view.

Ann Rees
Staff reporter
The Province
Vancouver, BC

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  1. Dormuth C, Anderson JF, Warren L. Caveat lector: be wary of media reports about excessive Ritalin use in BC [letter]. CMAJ 2000;162(3):313.
  2. Rees A. When it comes to kids taking Ritalin, BC's breaking records. Vancouver Province 1999 Aug 9;SectA:15.

[Editor's note:]

Ms. Rees was not given the opportunity to respond to the letter from Mr. Dormuth and colleagues in the issue in which it appeared. We apologize for this oversight.

© 2000 Canadian Medical Association or its licensors