sarkeizen's Journal: More poor logic by ltbarcly

Hmm, first time using this. Mostly due to clarifying some things said before comments closed on the following thread:

ltbarcly has some odd opinions:

"What you say is true. One symptom is not the disease. However, one symptom is a symptom of the disease, by hypothesis. So he has several of the symptoms (or characteristics which have a high level of correlation with the disease if you like) of ADD, as I previously pointed out."

Except that ltbarcly never pointed this out...what was originally said by ltbarcly was:

"Actually, that isn't 'flow'. It's Attention Deficit Disorder." Not, "this may be a sign of" or "this marginally increases your chance of having"...

Somehow also ltbarcly is claiming more than one symptom now (although later he/she seems to change his/her mind). How ltbarcly came to the conclusion that 'hyperfocus' (which isn't recognised as a symptom by the DSMIV) and the other characterisitcs are 'highly correlated' is left unsaid.

I'm going to step over the jawing about "Wiki being at least as accurate as gospel" since more than a few logical flaws are made and it's majoring (most of his/her text was dedicated to this subject) on a minor.

So after that ltbarcly goes on:

"I am not making a 'directional fallacy'. I am stating that he had one clear symptom of ADD."

Well not even, since (a) There appears to be little evidence to support the assertion that this is a symptom of ADD (see below) and (b) even if we were to write that symptom into the list in the DSMIV you still have the problem that it's unclear if it is being exhibited "to a degree that is maladaptive and inconsistent with developmental level"

So although ltbarcly has changed his/her tune - albeit by pretending he/she said something different than was actually said. This new position isn't quite supported either.

"If there is a higher than average statistical correlation of the presence of a symptom in a person and the presence of the disease,"

Here I'm begining to suspect that ltbarcly doesn't even understand what he/she is typing. What ltbarcly appears to be saying here is if something has greater than 50% correlation with a particular disease then it's a symptom if not it isn't. So something that occurs in 10% of patents isn't a symptom. Which is silly. There are plenty of diagnoses that depend on a series of conditional probabilities which only collectively give you a better than average chance at being diagnoses. Take for example the early screenings for certian birth defects. They rely on two samples of blood word, plus at least one ultrasound. The result? If you screen positive you still have a better than average probabilty of NOT having the disease.

"then if someone does exhibit the symptom they have a correspondingly higher likelihood of having the disease."

Here is another problem with ltbarcly's thinking but this time it's with math. The issue isn't about 'correspondance' it's about significance. Sure a symptom is related to the probability of having a disease but it doesn't have to be to a significant degree.

Take for example a disease that is incredibly rare ( striking say 1 in 1,000,000,000,000 ) but there's a test for it that is right 99.99% of the time. You can say that testing positive for this disease is a 'symptom' of having the disease but the probabily of having said disease even after testing positive isn't terribly signifcant ( you have a far, far, far better chance of not having the disease than having it).

The last bit is sad and funny.

"Besides, the wikipedia article, of you cared to read it, goes over in detail your objections, including hyper-focus not being in DSM - IV."

What medical facts it actually states are a few things.

1) There is no pubmed article with that term.
2) It isn't recognized by the DSM-IV.
3) It states, without a corresponding in-text cite that there is a 'well-recognised' (peacock word) comorbitity with another set of disorders that contain that as a part.

This is where ltbarcly clearly shows which side of the fence he/she is on concerning 'people who don't know how to not believe everything that they read'. That text does nothing to refute the idea that hyperfocus isn't a very good indicator of ADHD.

Essentialy ltbarcly is saying that it's ok to make a diagnosis ("This is ADHD") on the basis of something that isn't recognised by the clincial standard, doesn't appear to be backed by a published study and defend your diagnosis on the basis of a statement of unspecified origin that this disorder is somehow linked to another group of disorders where some people exhibit this aleged symptom.

Perhaps this is why he/she spent so much time defending the idea that the Wiki is as good as gospel.