Health Canada has issued ”œstronger, clearer” warnings about suicide risks linked to attention deficit/hyperactivity disorder drugs. Too bad they seem to ignore the Law of Small Numbers. In short, the plural of anecdote is not data but it sure is a recipe for misinformation and fear-mongering.

Anecdotal reports of side-effects/adverse-effects of medications are submitted to Health Canada. It is a process that includes self-reported information by patients, most of the time to their doctors. Their doctor then sends the information to Health Canada.

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The side-effects may not share a causal link with their medication use and is difficult to verify. Anecdotal reports should lead to further investigation to determine whether there is indeed correlation and causation. They are the first step to generate the questions for follow-up investigation. But this critical step is overlooked and the ”œconclusions” trumpeted in the headlines.

The logical fallacy of the Law of Small Numbers is displayed these news reports. It is the tendency to generalize from small amounts of numbers and come to a conclusion that may not necessarily be correct. This is similar to what happened to the Toronto Star and their Gardasil report linking the HPV vaccine to harmful side-effects in girls based on anecdotal reports. It was thoroughly debunked, the paper apologized, and a retraction of the story followed shortly thereafter.

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The same pole-vaulting begins anew with  the ADHD medication-suicide risk reports. Health Canada admits that ”œThere is little evidence to establish that these drugs cause suicidal thoughts and behaviours, but it is possible that they may contribute to the risk.” They admit that they cannot produce any new evidence or propose a biological mechanism of action to explain it. They do state that people diagnosed with ADHD ”œmay already have a slightly increased risk of suicidal thoughts and behaviours,” and that ”œADHD may also affect people who have other mental health conditions that are associated with an increased risk of suicide, such as depression or bipolar disorder.”

I think it is important to have a vigilant evidenced-based reporting system with verification procedures to ensure that we have valid data set to use. This is a powerful instrument to learn about possible new interactions between medications, discover new biological mechanisms of disease that may lead to better and safer medical  therapy, and to help prevent adverse effects from medications. This is not what is happening now. Instead we have a headline and story that can understandably scare parents and lead to unintended health consequences for their children based on misinformation.

Health Canada needs to do a better job in its communications and journalists should hold them accountable to produce verifiable evidence so that we have a realistic perspective of the risk and benefits of the medication that we use.

Barry Dworkin
Barry Dworkin is an assistant professor of family medicine at University of Ottawa, operates an active family/obstetric teaching practice of 25 years, and hosts the radio show "Sunday House Call." He loves to argue for cathartic health reasons.  

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