Saturday, 11 August 2012

Questionnaire Extremism and National Character

"Personality differences" between people from different countries may just be a reflection of cultural differences in the use of 'extreme' language to describe people.


That's according to a very important paper just out from an international team led by Estonia's René Mõttus.

There's a write up of the study here. In a nutshell, they took 3,000 people from 22 places and asked them to rate the personality of 30 fictional people based on brief descriptions (which were the same, but translated into the local language). Ratings were on a 1 to 5 scale.

It turned out that some populations handed out more of the extreme 1 or 5 responses. Hong Kong, South Korea and Germany tended to give middle of the road 2, 3 and 4 ratings, while Poland, Burkina Faso and people from Changchun in China were much more fond of 1s and 5s.

The characters they were rating were the same in all cases, remember.

Crucially, when the participants rated themselves on the same personality traits, they tended to follow the same pattern. Koreans rated themselves to have more moderate personality traits, compared to Burkinabés who described themselves in stronger tones.

Whether this is a cultural difference or a linguistic one is perhaps debatable; it might be a sign that it is not easy to translate English-language personality words into certain languages without changing how 'strong' they sound. However, either way, it's a serious problem for psychologists interested in cross-cultural studies.

I've long suspected that something like this might lie behind the very large differences in reported rates of mental illness across countries. Studies have found that about 3 times as many people in the USA report symptoms of mental illness compared to people in Spain, yet the suicide rate is almost the same, which is odd because mental illness is strongly associated with suicide.

One explanation would be that some cultures are more likely to report 'higher than normal' levels of distress, anxiety - a bit like how some make more extreme judgements of personality.

So it would be very interesting to check this by comparing the results of this paper to the international mental illness studies. Unfortunately, the countries sampled don't overlap enough to do this yet (as far as I can see).

ResearchBlogging.orgMõttus R, et al (2012). The Effect of Response Style on Self-Reported Conscientiousness Across 20 Countries. Personality and Social Psychology Bulletin PMID: 22745332

Friday, 10 August 2012

On Twitter, It's Beer Before Liquor

People tweet about beer in the evenings, especially on Fridays, according to a not-very-surprising-but-still-fun little report in the journal Epidemiology: Using Twitter to Measure Behavior Patterns


The study used timeu.se, a free searchable database of millions of Tweets. The site grew out of an excellent bit of research you might remember from last year that examined how average mood varies over the course of the day and year.

People tweet about and presumably drink beer (and wine) most in the evenings, especially on Fridays and Saturdays. Smoking-related tweets however were mostly flat, although there did seem to be a small peak in the mornings.

So I ran a few searches of my own, and I noticed that different drinks peak at different times. "Beer" is most popular in the early evening, closely followed by "Wine", but "Vodka" doesn't max out until midnight.

Looks like people are not following the old "beer before liquor, never sicker" rule.

Also, while wine gets the most tweets during the week, beer and vodka really take off at the weekend.

 ResearchBlogging.orgCunningham A. John (2012). Using Twitter to Measure Behavior Patterns Epidemiology DOI: 10.1097/EDE.0b013e3182625e5d

Tuesday, 7 August 2012

Brains In Motion Are Bad For Neuroscience

A new paper in Human Brain Mapping reports on: Functional magnetic resonance imaging movers and shakers: Does subject-movement cause sampling bias?

Head movement is a well known problem that can badly impact the quality of neuroimaging data, introducing spurious signals and obscuring real ones. It's an issue for all brain scanning research but according to Wylie and colleagues, authors of this paper, it's especially serious for studies comparing disease patients to healthy controls.

The authors got 34 people with multiple sclerosis (MS) to perform some simple cognitive tasks during fMRI scanning. They found that the harder the task was, the more the patients moved around during the scan; and in those with more severe MS, the correlation between difficulty and motion was even stronger. In healthy people, harder tasks only caused slightly more motion.

And the more people moved, the less brain activity was recorded, probably because movement degraded the data quality.
fMRI data associated with severe head movement is frequently discarded. In discarding these data, it is often assumed that head-movement is a source of random error, and that data can be discarded from subjects with severe movement without biasing the sample. We tested this assumption by examining whether head movement was related to task difficulty and cognitive status among persons with multiple sclerosis (MS).

[In the MS patients] there was a linear increase in movement as task difficulty increased that was larger among subjects with lower cognitive ability. Analyses of the signal-to-noise ratio (SNR) confirmed that increases in movement degraded data quality. Similar, though far smaller, effects were found in healthy control subjects. Therefore, discarding data with severe movement artifact may bias multiple sclerosis samples such that only those with less-severe cognitive impairment are included in the analyses. However, even if such data are not discarded outright, subjects who move more will contribute less to the group-level results because of degraded SNR.
Oh dear. fMRI researchers use two main ways to deal with motion - correction, and rejection. Either you try to take account of movement and analyze the data, or you just throw out the results from people who move a lot. Most people use a combined approach, chucking out the really heavy movers and then using correction on the rest.

This paper however shows that both techniques have problems. Despite motion correction, data from heavy movers has a lower signal to noise ratio, so if you include them, they will "dilute" your sample. However, if you chuck them, that'll also introduce bias, because heavy movement is not random - people with more severe MS move more, so by excluding heavy movers, you'll be excluding severe cases.

Informally, every neuroimaging researcher knows that some people move more than others. Learning to spot likely "movers" and avoid wasting money on scanning them is a fine art. In my experience just about every "patient" population move, on average, more than healthy controls, and children and the elderly move more than young adults.

I'm not sure there's an ideal solution but perhaps the best approach is to run all analyses (at least) twice, once including everyone, regardless of movement, and then again, with strict movement exclusion criteria. Results consistent across both analyses are probably solid.

ResearchBlogging.orgWylie GR, Genova H, Deluca J, Chiaravalloti N, and Sumowski JF (2012). Functional magnetic resonance imaging movers and shakers: Does subject-movement cause sampling bias? Human brain mapping PMID: 22847906

Friday, 3 August 2012

DSM-5 R.I.P?

Yesterday, the proposed new DSM-5 revision of the American Psychiatric Associations "Bible of Psychiatry" came under yet more criticism.



Aaron T. Beck, the father of currently-mega-popular cognitive behavioural therapy, started it off with an attack on the upcoming changes to one diagnosis, Generalized Anxiety Disorder; but many of the points also apply to the other DSM-5 proposals:
The lack of specific features, which is the primary issue for GAD, will not be addressed in DSM-5. The hallmark of the condition will remain pathological worry, although it also characterizes other disorders. Likewise, the proposed behavioral diagnostic criteria lack specificity for GAD, and it is not clear how these will be assessed. The proposed changes will lower the diagnostic threshold for GAD in DSM-5... many currently subthreshold cases will qualify for this diagnosis. The likely inclusion of many such "false-positives" will result in an artificial increase in the prevalence of GAD and will have further negative consequences.
Then from across the Atlantic, and also across the psychotherapy-vs-medication divide, came another piece of criticism. The authors are all associated with the European Medicines Agency (EMA, Europe's equivalent of the FDA), or with national drug regulators. Although they're writing in a personal capacity, this is still big news if you ask me.

These authors start out by saying that the EMA is broadly in favour of DSM reform, but they then attack one of the key DSM-5 innovations - the move towards 'dimensional measures' of symptoms in addition to diagnoses:
One of our main concerns is related to potential future [drug] indications based on an effect on a dimension that is independent of diagnostic categories (although we acknowledge that non-specific claims are common in other areas, such as analgesics for pain). As an example, cognitive impairments are common in psychiatric disorders, but they do not have a unique clinical pattern or a unitary cause.

We therefore believe that, at present, such a cross-cutting approach may increase heterogeneity in patient populations and make the assessment of the benefit–risk balance more difficult. Similarly, the use of dimensions as key secondary end points in many different diagnostic categories may lead to pseudospecific indications and polypharmacy. As a general rule, a therapeutic indication should be a well-recognized clinical entity that is clearly distinguishable from other conditions...
They also echo Beck in warning of over-diagnosis and over-medicalization:
Current proposals to reclassify some conditions that were subthreshold or prodromal as distinct syndromes or disorders could have implications for clinical trials. The inclusion of milder or very early cases of psychiatric disorders may lead to an increase in the number of non-disordered (false-positive) patients in clinical trials, and to an increase in the placebo effect, as less severe cases are more likely to respond to placebo. It may therefore be difficult to show a statistically significant difference [of drug over placebo]...
This raises another highly controversial issue: the risk of medicalization of the normal population. In this respect, a strong concern comes from the proposal to remove bereavement exclusion from the criteria for major depressive disorder, implying that all individuals with ‘normal grief’ might be considered as patients in the future.
Regular readers will remember that I've covered both overdiagnosis screwing up clinical trials, and the bereavement debate.

Two and a half years ago, shortly after the first draft of the DSM-5 was made public, I predicted that the eventual release of DSM-5 would be a non-event because, by then, it would have been widely debated and criticized, destroying the illusion of expert consensus that any such document must have in order to succeed.

I think events have borne this out. An awful lot of professionals, patients, and their relatives, will reject the changes in favour of sticking with the DSM-IV or other criteria. Without swift and general acceptance, a document like the DSM is just paper. It seems increasingly likely that the DSM-5 is going to be dead on arrival.

ResearchBlogging.orgStarcevic V, Portman ME, & Beck AT (2012). Generalized anxiety disorder: between neglect and an epidemic. The Journal of nervous and mental disease, 200 (8), 664-7 PMID: 22850300

Florence Butlen-Ducuing et al (2012). DSM‑5 and clinical trials in psychiatry: challenges to come? Nature Reviews: Drug Discovery DOI: 10.1038/nrd3811

Wednesday, 1 August 2012

Love Truth? Wait.

Britain may be hosting the Olympics, but that hasn't stopped us indulging in our own national sport of complaining. Many of the complaints in the past 24 hours or so have been about this chap:


Rileyy_69 attacked a celebrity on Twitter, who called him out on it, rileyy_69 attacked him more, thousands of fans of said celebrity attacked him, he attacked some of them back, then he apologized, but then attacked again, and eventually someone reported him to the police, and he was arrested on Tuesday morning for malicious communications or something.

All very exciting, but so what?

Should we pity this guy, or did it he bring it on himself? Were the thousands who attacked him jumping on the bandwagon, or justifiably outraged? Should he have been arrested, and if not, why? Because the law in question ought to be repealed, or because it's a fine law but was wrongly applied in this case?

Good questions. We don't know enough yet to answer them. We don't know this person, his life story, his mental health situation, etc. Some details have now started to emerge, but generally the early, fragmentary reports in cases like this only add to the confusion.

It's too early to tell. I don't think anyone can dispute this. Unless you i) know Rileyy69 in real life and ii) are an expert in the relevant areas of law and iii) have read all his Tweets, not just the ones that made it into the newspapers, you are probably not in a position to judge.

It's too early to say, but that's never stopped anyone.

Newspapers and blogs are full of definitive, final judgements on these questions. Both those broadly in favor of the arrest of Rileyy_69, and those opposed, are equally premature. If there is a difference, it's that the latter group also include hypocrites, who swiftly took to Twitter to criticize the knee jerk mob mentality of the Twitterati.

One who really cared about Rileyy_69, the law, the media, or whatever else they claimed to, would above all want to establish the facts before commenting. The truth will out; we can but wait, or try to help it along. But we should not try to outrun it.

The truth is slow.

And that's fine. There's rarely, and certainly not in this case, a need to form your opinions within minutes and to nail your theses to the door of the cathedral within a day of the event. Just wait! You'll be in good company; few of the great minds of history measured time in hours.

"Ah", you might say, "but those who attacked Rileyy_69 on Twitter were, themselves, doing what you're criticizing!". They were, actually, but that's what Twitter is for. Tweets are about speed and in its place, that's fine. The human brain responds to stimuli within about 100 milliseconds; you give people the chance to type that response, and they will. To criticize that is to criticize human nature.

No, the problem is not those who use an avowedly instant communication service as intended. It's those who try to export that mode of thought into the ancient and higher medium of prose longer than 140 characters.

For everything there is a time, a time to Tweet and a time to think. Just don't mix them up.