I’m with wnoise, but I have a question to clarify my position.
How many diagnoses do you expect a competent physician to get wrong? I would say that more than 1 in 20 is at least reasonable. However, without meeting CronoDAS, or performing tests of any kind, based purely on the scant evidence in his posts, you have diagnosed him with a micronutrient deficiency, and have a confidence of 95% in your diagnosis. Seriously? What’s your prior? Even for thiamine, a 60% confidence that this near-stranger is deficient in it seems dramatically too high.
How many diagnoses do you expect a competent physician to get wrong?
I expect physicians to be bewildered rather a lot. I spent years severely anemic. My father is an MD, my uncle is an MD, I saw a variety of doctors during this time, I was eating cups and cups and cups of ice every single day and was unremittingly tired and ghostly pale, partway through I became a vegetarian—and it took the Red Cross’s little machine that goes beep to figure out that maybe I wasn’t getting enough iron. I have a vast host of symptoms less serious than that which no doctor, med student, or random interlocutor has been able to offer plausible guesses about.
Agreed. Even if they don’t make things up, the responsible thing to do is to iterate through harmless or nearly-harmless treatments for conditions that the physician thinks are unlikely, but more likely than any other ideas he or she has.
This is exactly the opposite problem; not being at all bewildered or in doubt, despite a paucity of evidence. Doctors do that too.
Both making things up and jumping to conclusions happen because doctors are humans and are wired to see patterns, whether or not they exist. While we’re busy refining the art of human rationality, we ought to try to curb that behavior.
These numbers are uncalibrated estimates (I spent 60s looking for population statistics to use as priors, and didn’t find any), but I don’t think they’re at all unreasonable. Keep in mind that deficiencies come in degrees, and only the most severe ones ever get diagnosed. Anyways, here’s a breakdown (again, just estimates) of that 0.95:
I certainly wouldn’t say it’s the only problem, but it’s very likely a contributing factor.
Anyways, we can find this out directly. CronoDAS, could you take a look at the wikipedia page on thiamine, go through the lists of thiamine-containing and thiaminase-containing foods, and estimate your intake? Or better yet, order sulbutiamine and report its effects here?
I would go as high as 0.3 if you extend to third world countries, but suspect it’s lower among people like ChronoDAS who can afford a variety of food. Either way, it’s good enough.
P(micronutrient deficiency|no multivitamin) = 0.8
The law of conditional probability indicates that you think that a minimum of 75% of the population takes a multivitamin. I think this is way too high, especially for a population that has a 20% micronutrient deficiency rate.
So the rate of depression among those with micronutrient deficiencies (and who don’t take their vitamins) is about 119% that of the general population? I can buy that, but if it’s that low, then why are you so sure that a micronutrient deficiency is “greatly contributing” to his depression?
I agree that there’s no harm in having CronoDAS gather data or experiment a little, since sulbutiamine seems to have very few negative side effects with recommended doses.
My main reason for brining it up is that I see some very high probabilities tossed about on Less Wrong, and it bothers me when I feel like they’re assigning numbers that they can’t justify. I’m still skeptical about your 95% confidence, but it’s nice to see a break down.
Would you be willing to take a bet at a 2/3rds payoff that CronoDAS has no thiamine deficiency? How about a 1/19th payoff that taking a daily multivitamin wouldn’t significantly alter how he feels?
[EDIT: Revised payoffs in bet to reflect professed certainty]
Thiamine is found in a wide variety of foods at low concentrations. Yeast and pork are the most highly concentrated sources of thiamine. In general, cereal grains are the most important dietary sources of thiamine, by virtue of their ubiquity. Of these, whole grains contain more thiamine than refined grains, as thiamine is found mostly in the outer layers of the grain and in the germ (which are removed during the refining process). For example, 100 g of whole-wheat flour contains 0.55 mg of thiamine, while 100 g of white flour contains only 0.06 mg of thiamine. In the US, processed flour must be enriched with thiamine mononitrate (along with niacin, ferrous iron, riboflavin, and folic acid) to replace that lost in processing.
Some other foods rich in thiamine are oatmeal, flax, and sunflower seeds, brown rice, whole grain rye, asparagus, kale, cauliflower, potatoes, oranges, liver (beef, pork and chicken), and eggs.
Hmmm… as it turns out, I’ve been eating quite a lot of thiamine-fortified pasta lately, and it’s also in cold cereal, orange juice, and bread. I don’t think I have an unusually low amount of thiamine in my diet when compared to the average American.
I’m with wnoise, but I have a question to clarify my position.
How many diagnoses do you expect a competent physician to get wrong? I would say that more than 1 in 20 is at least reasonable. However, without meeting CronoDAS, or performing tests of any kind, based purely on the scant evidence in his posts, you have diagnosed him with a micronutrient deficiency, and have a confidence of 95% in your diagnosis. Seriously? What’s your prior? Even for thiamine, a 60% confidence that this near-stranger is deficient in it seems dramatically too high.
I expect physicians to be bewildered rather a lot. I spent years severely anemic. My father is an MD, my uncle is an MD, I saw a variety of doctors during this time, I was eating cups and cups and cups of ice every single day and was unremittingly tired and ghostly pale, partway through I became a vegetarian—and it took the Red Cross’s little machine that goes beep to figure out that maybe I wasn’t getting enough iron. I have a vast host of symptoms less serious than that which no doctor, med student, or random interlocutor has been able to offer plausible guesses about.
I expect bewildered people to make things up.
Agreed. Even if they don’t make things up, the responsible thing to do is to iterate through harmless or nearly-harmless treatments for conditions that the physician thinks are unlikely, but more likely than any other ideas he or she has.
This is exactly the opposite problem; not being at all bewildered or in doubt, despite a paucity of evidence. Doctors do that too.
Both making things up and jumping to conclusions happen because doctors are humans and are wired to see patterns, whether or not they exist. While we’re busy refining the art of human rationality, we ought to try to curb that behavior.
These numbers are uncalibrated estimates (I spent 60s looking for population statistics to use as priors, and didn’t find any), but I don’t think they’re at all unreasonable. Keep in mind that deficiencies come in degrees, and only the most severe ones ever get diagnosed. Anyways, here’s a breakdown (again, just estimates) of that 0.95:
I certainly wouldn’t say it’s the only problem, but it’s very likely a contributing factor.
Anyways, we can find this out directly. CronoDAS, could you take a look at the wikipedia page on thiamine, go through the lists of thiamine-containing and thiaminase-containing foods, and estimate your intake? Or better yet, order sulbutiamine and report its effects here?
I would go as high as 0.3 if you extend to third world countries, but suspect it’s lower among people like ChronoDAS who can afford a variety of food. Either way, it’s good enough.
The law of conditional probability indicates that you think that a minimum of 75% of the population takes a multivitamin. I think this is way too high, especially for a population that has a 20% micronutrient deficiency rate.
So the rate of depression among those with micronutrient deficiencies (and who don’t take their vitamins) is about 119% that of the general population? I can buy that, but if it’s that low, then why are you so sure that a micronutrient deficiency is “greatly contributing” to his depression?
I agree that there’s no harm in having CronoDAS gather data or experiment a little, since sulbutiamine seems to have very few negative side effects with recommended doses.
My main reason for brining it up is that I see some very high probabilities tossed about on Less Wrong, and it bothers me when I feel like they’re assigning numbers that they can’t justify. I’m still skeptical about your 95% confidence, but it’s nice to see a break down.
Would you be willing to take a bet at a 2/3rds payoff that CronoDAS has no thiamine deficiency? How about a 1/19th payoff that taking a daily multivitamin wouldn’t significantly alter how he feels?
[EDIT: Revised payoffs in bet to reflect professed certainty]
From Wikipedia:
Hmmm… as it turns out, I’ve been eating quite a lot of thiamine-fortified pasta lately, and it’s also in cold cereal, orange juice, and bread. I don’t think I have an unusually low amount of thiamine in my diet when compared to the average American.