Thursday, January 3, 2013

ADHD: More Misleading Propaganda

In the never ending effort to con the world in general, and physicians in particular, into thinking that most inattentive and rambunctious children and adults have a neurobiological disease, a Dr. Samuele Cortese and his colleagues presented yet another MRI study that they allege shows that children and adults who have been diagnosed with ADHD have abnormalities in their brains. 

Dr. Cortese is listed as a consultant for Shire Pharmacueticals, a major manufacturer of stimulant drugs for “ADHD.” Or as some might say in ordinary language, Shire is a drug dealing syndicate. One of the most egregious examples of same, at that. Shire’s interests are served by having the largest number of people taking their “legal” amphetamines as possible, while also spreading the word that their competition, “illegal” amphetamines, are dangerous and highly abused drugs.

I use the word “diagnosed” with ADHD in the first paragraph above rather than “have” ADHD because, as I have demonstrated in previous posts, the evaluation of patients who seem to have these problems leaves out an entire and absolutely essential part of their lives – the behavior of their families that provides a context for the child’s “symptoms.” 

No effort, or only a half-baked one, is made in these studies to differentiate acting out from other possible causes for the patient’s hyperactive behavior or difficulties in maintaining focus.

The new study, published in the issue of the American Journal of Psychiatry, proves the following point beyond a shadow of a doubt: people who are not paying good attention to a particular task in which they are engaged exhibit less activity in those brain centers involved in paying attention to tasks than people who are paying strong attention.  Wow. Who’d’a thunk it?

And as we all know, any difference simply must be an abnormality.

In fact, the study says absolutely nothing about whether these research subjects cannot pay attention or simply are not paying attention.

The study in question (Cortese et al, “Toward Systems Neuroscience of ADHD: A Meta-Analysis of 55 fMRI Studies,” Am J Psychiatry 2012; 169:1038-1055) combines statistics from 55 different studies of ADHD, many of which use very different diagnostic “tests” which are merely symptom report lists and pay little attention to the pervasiveness of the symptoms, let alone the psychosocial context in which the symptoms take place.

Here are the results. Hypoactivation is a term meaning that the affected part of the brain is less active, on average, than it might be in a comparison subject. Of course, how active such a brain part might depends strongly on the motivations of the particular subjects. (This is analogous to the results of IQ tests, which are biased against those people who don’t give a damn about how well they do on the test).  Hyperactivation means the opposite.  

Surely, whether more or less activity in a region of the brain is pathological is entirely pre-supposed by the authors without any valid justification. It is basically a value judgment.

“Fifty-five studies were included (39 for children and 16 for adults). In children, hypoactivation in ADHD relative to comparison subjects was observed mostly in systems involved in executive function (frontoparietal network) and at­tention (ventral attentional network). Sig­nificant hyperactivation in ADHD relative to comparison subjects was observed predominantly in the default, ventral at­tention, and somatomotor networks. In adults, ADHD-related hypoactivation was predominant in the frontoparietal system, while ADHD-related hyperactivation was present in the visual, dorsal attention, and default networks. SignificantADHD-related dysfunction largely reflected task features and was detected even in the absence of comorbid mental disorders or a history of stimulant treatment.
Conclusions: A growing literature pro­vides evidence of ADHD-related dysfunc­tion in multiple neuronal systems involved in higher-level cognitive functions but also in sensorimotor processes, including the visual system, and in the default net­work. This meta-analytic evidence extends early models of ADHD pathophysiology that were focused on prefrontal-striatal circuits.”
The studies being "meta-analyzed" are designed on purpose to make it appear that normal differences mean something other than their just being normal differences.
Let us look at the distribution of how strongly people “pay attention” to boring tasks to which they have no particular motivation to do well (other than their desire to be co-operative with an experimenter). Most of the tasks during which brain activity is measured are, let’s face it, at least somewhat uninteresting.
This distribution, like almost everything else in nature, will look like a bell-shaped curve, or what is called normal distribution. We don’t even have to invoke the fact that some people may habitually pay less attention to most activities because they might be compulsively and habitually playing a role ["unambitious"] within their family of origin that allows them to get labeled as having ADHD.

The self report instruments and diagnostic interviews through which a diagnosis of ADHD is made will, in effect, sort the patients so that those labeled with ADHD will fall, on average, at point A on the bell shaped curve in the figure above. Since those individuals will then be taken out of the pool of study subjects, those that remain will have an above average tendency to pay attention to boring tasks – their average will be at point B in the diagram.
Everything else being equal, the “ADHD” subjects and the control control subjects could all be completely normal, and the study result would be identical to a study in which a real disease were being studied! The authors have no way of knowing which of these possibilities their study is demonstrating. They do not clearly acknowledge the above considerations as a weakness of the study, although they do concede, “fMRI data cannot define an absolute or quantitative baseline of activation…” (p. 1053).

That disclaimer is added to give the authors plausible deniability, and will of course be completely ignored by readers if it is noticed at all.
The authors start their discussion of their results with the sentence, “ADHD is increasingly being conceived of as a disorder underpinned by dysfunctions in multiple large scale brain networks.” Yeah, because of pseudo-scientific conclusions made from a multiplicity of studies done the way this one was.

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