Saturday, April 02, 2011

ADHD quackery in scientific journal, again

I was not intending to blog on scientific themes these days, but sometimes duty calls. Carelessly browsing the Web, I suddenly found a link that switched all my alarms on. Briefly, it refers the reader to an article by Pelsser et al. titled Effects of a restricted elimination diet on the behaviour of children with attention-deficit hyperactivity disorder (INCA study): a randomised controlled trial and published in the February issue of the Lancet. I have no access to the full text, but the abstract tells us that from 100 children with ADHD aged 4-8, a randomly chosen half were left as controls and the other half were put for 5 weeks on a restricted elimination diet. There is no mention what this diet was, and the results are described in such a messy way that it is impossible to understand exactly what is claimed. Happily, the same Web site directs the reader also to a LA Times article by Jill Adams discussing the study. It informs us that the restricted diet consisted of "short list of ingredients that included water, rice, turkey, lamb, lettuce, carrots, pears and other hypoallergenic foods". "At the end of the study, 64% of the kids on the limited diet showed significant improvement on a variety of standard rating scales. Though the initial scores for all of the kids in this group put their ADHD symptoms in the moderate-to-severe range, after the diet intervention their symptoms were classified as either mild or nonclinical."

Three years ago, I wrote a post titled I am skeptical about food additives - hyperactivity link. It questioned another publication in the Lancet claiming that "artificial food colous and additives" were causing ADHD symptoms. If you are interested in the subject, you can read that old post, too. In the present post, I will not try to keep the same line of composed argumentation. I am furious and not going to hide it.

Are you worried about the quality of the food you consume? Are you anxious to obtain healthy food and to give it also to your family members? And if so, what are you thinking of yourself? Perhaps you think you are a responsible person and everybody should be like you. Unfortunately, this has nothing to do with the truth. You are victim of a disorder which turns your life into hell and endangers your physical health - and that of any child with the poor luck to be under your care. The obsession with healthy foods is a disorder called orthorexia by some psychiatrists. It is not an official diagnosis but is easily accommodated under the umbrellas of eating disorders and obsessive-compulsive disorder. My observations show that many people with real or imagined health problems, and particularly parents of chronically ill and disabled children, develop orthorexia. They swear that their or their child's condition has been caused by unhealthy eating and is currently ameliorated by some particular "healthy" diet. Here, "healthy" diet typically means one that, if given to convicted felons, will lead to prison riots and charges with inhumane treatment. The list of publications of the first author of the study in question - Dr. Pelsser, is not too impressive but clearly shows that she has orthorexic obsession about ADHD.

People of science have a saying that extraordinary claims require extraordinary evidence. Any claims for successful treatment of a socially important condition are extraordinary, and so are any claims based on an insane working hypothesis. If you ask me what hypothesis I call insane, I'll answer that I cannot give a definition but the hypothesis of foods causing abnormal behaviour is a brilliant example.

I would ask again, as I did in my old post, why wasn't the study done first on animal models? And if someone thinks animal models of ADHD are not satisfactory (i.e. fail to produce the crazy results wanted and expected by the researcher), why wasn't the experiment done first on adult volunteers with ADHD? Maybe because no adult, except some patients with much more severe diagnoses than ADHD, would agree to participate in such a study; but parents eager to streamline their disabled or just different children easily fall into the trap of wanting the child "either cured or dead". In the LA Times article, Dr. Pelsser says, "The children said they felt so different, as if some mad thing in their head wasn't there anymore". Eh well, if your 5-yr-old experimental subject talks of "some mad thing in his head", you should bury your own head in your hands, then abort the study and pray that your institution's ethical committee never hears of this. Has the whole world gone crazy?

The Lancet is a top scientific journal with an impact factor of 30 (for lay people - this is sky high). Such a journal, especially if specialized in clinical medicine, is expected to have a take-no-prisoners peer review that would not let any crap sneak in. However, this journal 13 years ago published the disastrous (now retracted) study linking the MMR vaccine to autism, it published the mentioned article linking food additives to ADHD 4 years ago, and has now published another nonsense about ADHD. When will the respectable Lancet raise its bar for quacks and stop shouting "Fire!" in crowded theaters?

1 comment:

K said...

What I find worrying is that even popular blogs dedicated to fighting quackery are nto educated about ADHD. For example this entry over at Bad Science:
I wanted to express my dismay, but someone had already done so in the comments:

А тук в българия известен психолог съвсем уверено ми твърдеше че ADHD било "предимно при деца" и имало "кампании от големите фармацевтични компании"... Тоя човек изобщо чете ли някаква научна литература по специалността си или се информира от някакви "alternative medicine" fear-mongers. Слава богу, не всички български специалисти в областта са като него.