Shyness By Any Other Name

People think of "social anxiety disorder" as more serious than "social phobia" - even when they refer to exactly the same thing.

Laura C . Bruce et al did a telephone survey of 806 residents of New York State. They gave people a brief description of someone who's uncomfortable in social situations and often avoids them. The question was: should they seek mental health treatment for this problem?

When the symptoms were labelled as "social anxiety disorder", 83% of people recommended treatment. But when the same description was deemed "social phobia", it dropped to 75%, a statistically significant difference.

OK, that's only an 8% gap. It's a small effect, but then the terminological difference was a small one. "Anxiety disorder" vs "Phobia" is about a subtle a distinction as I can think of actually. Imagine if one of the options had been a label that didn't imply anything pathological - "social anxiety" or "shyness". That would probably have had a much bigger impact.

This matters, especially in regards to current debates over the upcoming DSM-5 psychiatric diagnostic manual. Lots of terminological changes are planned. This study is a reminder that even small changes in wording can have an impact on how people think about mental illness. Last week I covered another recent piece of research showing that beliefs about other people's emotions affect how people rate their own mental health.

My point is: DSM-5 will not merely change how professionals talk about the mind. It will change how everyone thinks and behaves.

Bruce, L. (2012). Social Phobia and Social Anxiety Disorder: Effect of Disorder Name on Recommendation for Treatment American Journal of Psychiatry, 169 (5) DOI: 10.1176/appi.ajp.2012.11121808

Scanning The Acidic Brain

According to University of Iowa researchers Vincent A. Magnotta and colleagues, any neuroscientist with an MRI scanner could soon be able to measure the acidity (pH) of the human brain in great detail: Detecting activity-evoked pH changes in human brain.

If it works out, it would open up a whole new dimension of neuroimaging - and might be able to answer some of the biggest questions in the field.

The method relies on measuring T1 relaxation in the rotating frame (T1ρ). Essentially, it's about the rate at which protons are swapped between water molecules and proteins. That rate is known to depend on pH.

Anyway. It certainly looks impressive. Using a standard 3 Tesla MRI scanner, they were able to image the whole brain once every 6.6 seconds - only slightly slower than conventional fMRI measurements of brain activity, where 2 or 3 seconds is more usual. The spatial resolution was comparable to fMRI.

Here's how it did on some bottles of jelly -

Then they moved onto mouse brains (the differences are smaller here)...

And finally they scanned some people. They were able to detect the (very small) pH changes caused by hyperventilation, which raises pH, and breathing air enriched in carbon dioxide, which lowers it.

Lovely pictures I'm sure you agree, and it's a very clever methodology from a technical point of view. But what will it mean for neuroscience?

Well, for one thing, it might be able to help resolve some of the debates over what conventional fMRI is actually measuring. For example, some neuroscientists believe that many (seemingly) interesting fMRI results may actually be (at least partially) reflections of subtle changes in breathing rate. Measuring acidity, an indirect proxy for breathing, could start to answer such questions.

The main question though is, what are we going to call the new method? "T1ρ MRI"... not a terribly catchy name.

Maybe MRalkalI?

Magnotta, V., Heo, H., Dlouhy, B., Dahdaleh, N., Follmer, R., Thedens, D., Welsh, M., and Wemmie, J. (2012). Detecting activity-evoked pH changes in human brain Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1205902109

The 70,000 Thoughts Per Day Myth?

Following on from a discussion on Twitter, I've been trying to find out the origin of the strange meme that the average person has "70,000 thoughts per day".

That's a lot of thoughts. It's about 3000 per hour or 50 per minute, just under one per second.

A lot of people believe this, according to Google. Even that esteemed neuroscientist and philosopher Dr Deepak Chopra agrees, although - being a rigorous, skeptical scientist, he acknowledged some error in his measurements and said "60,000 to 80,000".

But where does this number come from?

Searching for the source, I discovered that 70k is only one such estimate. Other popular figures include 15k ; 60k ; and "12k to 50k". This last one is the only number that ever seems to come with a citation as to the source: it's attributed to "The National Science Foundation (NSF)".

This claim was made at least as far back as 2003 by a certain Charlie Greer ("Helping Plumbing, HVAC, and Electrical service contractors Sell More at Higher Profits").

But the NSF is a funding organization. Their main job is to hand out US government money to all kinds of different researchers. They don't do research as such, or at least not much, so it seems unlikely that the NSF actually said this. Perhaps they funded the research that did. But whose research? I can't find any specific sources at all.

One suggestion made on Twitter was that it could derive from Daniel Kahneman's idea that the "psychological present" is a window of about 3 seconds - everything else is either past or future.

Kahneman has in fact used NSF funding, although so have most scientists in the USA.

Now Kahneman himself said in a talk recently that there are 600k of these "psychological presents" per month, i.e. 20k per day. If you divide a day into 3 second chunks you get about 29k a day, but I guess if you assume we're asleep for a third of the day that makes 20k.

OK. I'm not sure life is really composed of neat equal chunks like that, and anyway, those are chunks of experience, not "thoughts"; but even if you ignore that, the weird thing is that very few people think we have 20k thoughts per day. 70k is far more common on Google.

Does anyone know where this number comes from?

Child Bipolar Disorder Still Rare

Bipolar disorder usually strikes between the ages of 15 and 25, and is extremely rare in preteens, according to a major study: Age at onset versus family history and clinical outcomes in 1,665 international bipolar-I disorder patients

The findings are old hat. It's long been known that manic-depression most often begins around the age of 20, give or take a few years. Onset in later life is less common while earlier onset is very unusual.

The main graph could have been lifted from any psychiatry textbooks of the last century:

The red bars are the data. Ignore the black line, that just shows an imaginary 'even' distribution over the lifespan.

Why am I blogging about these remarkably unremarkable results? Because they undermines the theory, popular in certain quarters but highly controversial, that 'child bipolar' or 'pediatric bipolar' is a major health problem.

The study confirmed that early-onset bipolar I does exist, but just 5% of the bipolar I patients had an onset before the age of 15. Assuming a lifetime prevalence of 1% for bipolar I disorder, which is about right, that makes about 0.05%, 1 in 2000 kids, about the same prevalence as Down's Syndrome. Even that's an overestimate, though, because this sample was enriched for early-onset cases: some of the participating clinics were child and adolescent only.

There's a few caveats. This was a retrospective study, that took adults diagnosed bipolar, and asked when their symptoms first appeared. It's possible that early onset cases were under-sampled, if they were less likely to survive to adulthood, or get treated. The generally milder bipolar II might also be different from the bipolar I studied here. But in general, these numbers support the traditional view that childhood bipolar is just not very prevalent.

Baldessarini, R., Tondo, L., Vázquez, G., Undurraga, J., Bolzani, L., Yildiz, A., Khalsa, H., Lai, M., Lepri, B., Lolich, M., Maffei, P., Salvatore, P., Faedda, G., Vieta, E., and; Tohen, M. (2012). Age at onset versus family history and clinical outcomes in 1,665 international bipolar-I disorder patients World Psychiatry, 11 (1), 40-46 DOI: 10.1016/j.wpsyc.2012.01.006

Politics: A Dialogue

"There's no point in voting. All the parties are the same."

"Hang on. Are you saying the Communists are the same as the conservatives? And that they're both the same as the Nazis?"

"Well, I meant all the main parties are the same."
"OK. But what's a main party?"

"A party that gets most of the votes, of course."

"Right. So by saying the main parties are the same, you're saying that most people broadly agree about politics."

"Erm... yes, but when you put it that way it seems much less fun. Anyway, I for one reject the discredited status quo and support..."

"...the Nazis."

"No! How dare you call me a Nazi?"

"You effectively are behaving as one. You're not voting against them. Which has the effect of helping them."

"That's ridiculous. I like Schindler's List as much as the next guy. I hate Nazis!"

"Just not enough to do the one thing they don't want, to vote against them."

"Erm... look, don't blame me. Blame mainstream politicians. They're the ones who've made people disillusioned. They're out of touch, and don't understand everyday people like me."

"They understand you well enough to convince you to vote for them, or at least not against them. Well enough to make you believe that they'll always be in power, that they are the natural leaders. I think they understand you all too well."

"That's not what I mean. I want people like me to be in power."

"Well, run for office then."

"Ha! I'd lose."

"Why?"

"Because..."

"Because people like you, wouldn't vote for you."

"That's crazy. Of course I'd vote for me."

"Would you? Someone like you was probably on the ballot, as an Independent or a minor party candidate, but I bet you didn't check. You just decided there was no point, because he would never win."

"And I was right!"

"Don't you see the problem? You're only right, because people like you think you're always going to be right. It's a self-fulfilling prophecy that you'll lose. That's the problem with your party!"

"My party? I'm not in a party!"

"You are, you just don't know it. A party is a group sharing common interests and beliefs. There are lots of people like you. Everyone is in a party; some of the parties are just badly organized, and don't get any votes or representatives."

"Because we don't want power!...wait...or do we?"