Irritable bowel syndrome-mens morba in corpore morbo

The stiff-upper-lips of this world will probably always claim that irritable bowel syndrome (IBS) is "just" or "only" IBS. However, this syndrome can be highly painful and even debilitating at its most severe. It is characterised by abdominal pain and bloating, as well as constipation and/or diarrhoea. It tends to be associated with high levels of stress; childhood trauma is more prevalent in people with IBS, who have also been shown to have an altered stress response to an acute stressor in not one but two studies. IBS is also comorbid with certain stress-related disorders such as depression, although the interaction between depression and IBS can sometimes be complex-see this clip with Kurt Cobain, who suffered from both IBS and suicidal ideation for an example.

Recent research from our group (particularly Paul Kennedy, who completed his PhD in this area) has suggested that people with IBS perform more poorly on a test of memory than a healthy control group. The test (paired associates learning) involves remembering the location of abstract shapes hidden behind boxes-a bit like the kind of card game one would play as a kid. It is thought to involve activation of the hippocampus, a brain region which is also involved in the regulation of the stress response. It should be noted that although the number of errors people with IBS were making was higher than the healthy group, this was a subtle difference-but a noticeable one nonetheless.

In a just published study which I had the good fortune to get involved with, we looked at the potential neurochemical underpinnings of this change in memory performance. Specifically, we looked at whether memory performance in IBS could be changed by altering tryptophan levels. Tryptophan is an essential amino acid ("essential" because we have to derive it from our diet). It's used by the body to produce serotonin-a household name among neurochemicals thanks, among other things, to the class of antidepressants known as SSRI's (selective serotonin reuptake inhibitors). HOWEVER, most tryptophan is broken down along the less-famous kynurenine pathway, where is it catabolised into kynurenine and various other neuroactive chemicals. The enzymes in our bodies which make this happen, such as IDO and TDO, have previously been found to be altered in IBS, and there is some evidence that the chemicals produced in the kynurenine system can have a negative impact on memory. This suggests the kynurenine system could play a role in IBS-related memory attenuation.

In our study we gave people with IBS and healthy controls a drink with amino acids other than tryptophan-these compete with tryptophan at the blood-brain barrier, and consequently reduce the amount of tryptophan getting through to the brain. As a control condition, on a different testing day we gave them the same drink but with tryptophan included. We then had everyone complete a series of cognitive tasks.

What the results indicated was that people with IBS did worse than healthy controls at the memory task, similar to what had been shown before. However, this only happened when they had consumed the drink containing tryptophan. Analysis of their blood samples by Gerard Clarke indicated that the drink containing tryptophan led to higher levels of kynurenine-thus breakdown of tryptophan along the kynurenine system may explain this memory difference in IBS.

As drinking a mix of amino acids can taste unpleasant I wouldn't necessarily advise people with IBS to run to the health shops to see if they have them in. I would say that one useful step people with IBS can take is to try to keep stress at a manageable level-excessive stress is likely to lead to negative impact on your cognitive performance, particularly in the case of more complex tasks such as remembering large amounts of info. Further, although there is no cure for IBS, symptoms can be managed and minimised, and avoiding too much stress is part of this process.

***UPDATE*** For those who want to know more about the science of IBS, I forgot to mention that while  I was working on this blog post Paul Kennedy et al. published a review paper looking at irritable bowel syndrome and the microbiome (i.e. the community of microorganisms living inside us humans, and their genes). Check it out!

Kennedy, P.J., Allen, A.P., O’Neill, A., Quigley, E.M.M._, Cryan, J.F., Dinan, T.G., Clarke G. (2014). Acute tryptophan depletion reduces kynurenine levels: Implications for treatment of visuospatial memory performance in irritable bowel syndrome. Psychopharmacology, doi: 10.1007/s00213-014-3767-z

Two different ways: Creativity and two modes of thought

Whenever one encounters a child genius one is tempted to think that their creativity cannot stem from "normal" thought processes, and one sometimes sees in DVD commentaries some writers and directors can have a surprising lack of insight or ability to articulate where their ideas come from-this can be the case with actors too. A lot of people assume that creativity is fundamentally mysterious-after all, they may say, if we fully understood it how would it be creative? Let's imagine one is not Mozart, but wishes to engage in a task which requires at least moderate creativity-let's say writing a script for a romcom which will hopefully earn loads of money. Is one doomed to wait upon some elusive muse, or can we think about the types of underlying thought processes one has to draw upon to complete this task?

In discussing this I draw on a distinction from the broader literature on thinking and reasoning. There has been a lot of interest in type 1 and type 2 thinking, which have been popularised in a recent book by behavioural economist extraordinaire Daniel Kahenman. A bat and a ball cost 1.10 - if the bat costs one euro more than the ball, how much do they cost? Type 1 thinking is fast and automatic (it shouts out "the bat's one euro and the ball's ten cent!), type 2 is slower and sequential (it realises that one euro is not one euro more than ten cent, so you have to adjust the estimate-it's actually 1.05 for the bat and five cent for the ball). I like to remember which is which by thinking of type 1 as the type which arrives first, because of its speed, and vice versa. The mysterio approach to creativity would seem to favour the account that, inasmuch as creativity is a thought process, it should therefore by type 1 (indeed, so fast that it is not accessible to conscious introspection). 

When working through creative projects, one tends to go through stages-firstly, you prepare the groundwork; say, checking out the other films in the genre to see if you are sinking into cliché (or committing outright plagiarism). There often follows an impasse, where one is stuck on what to do next-where to go relative to what's gone before (how many ways can you get two kooky singletons to go through the will-they/won't-they and maintain tension in the audience?). Following a period of "incubation" with a bit of luck there is then insight; the aha! moment when it occurs to you how to move past the mental block (the unique selling point of the script is the male lead is actually a salmon trapped in the body of a windsurfing CEO played by Matthew McConaughey). But often the creative process doesn't end there- you then have evaluation of the idea ("the salmon thing isn't realistic, but is it compelling?") and then dissemination (having the script sent to directors/producers who realise your meisterwork on the big screen). There are other accounts of creativity that propose more stages, but I think this broad framework is a nice place to start.

I have argued previously in an article with Kevin Thomas that both type 1 and type 2 thinking are important at various stages of creative thinking. During the preparation phase, ideas for creative projects can come through applying simple heuristics (e.g. "do the opposite of what they've done") or through careful consideration of what your predecessors have done. Insight can be a very sudden thing (many riddles used in psychology experiments can be like this) or it can occur through a more gradual process of working through concepts (consider the process of composing a score for a film; there are many points at which you have to decide which ntoes to use next). Evaluation can be type 1 ("does the script for the romcom look okay?") or type 2 ("how exactly should I phrase the funeral speech to avoid undermining the frothy comedy?") 

It's always flattering when one's work is cited and it was cool to see our paper get cited in a recent article in Thinking & Reasoning which indicated that people prone to engage in type 2 thinking perform better at the remote associates test (e.g. "what word connects the three words HOUSE, APPLE and SURGEON?") This test is thought to tap into the slope of one's associative hierarchy (basically, the ease with which one can draw connections between concepts which, at first glance, may seem unconnected). Such a skill is surely important for the striking juxtapositions that can create a great scene in a novel or film. At the same time, the remote associates test is very quick- in terms of stages of the creative process it tends to be associated with a very sudden moment of insight and very little evaluation. It would be interesting to see more research being done on the more long-term creative thinking projects that artists engage in, where insight happens at a more gradual pace (e.g. choosing various chords in the writing of a song) and evaluation of a larger set of ideas must be carried out (e.g. honing the phrasing of the quips Jennifer Lawrence speaks as her six-packed beau flounders on the beach in salmon-brained lunacy). 

Since writing the paper with Kevin Thomas, I also came across evidence that what can aid creativity is using whichever type of thought one is less likely to rely upon generally. It seems that maybe it is not just the ability to use both slow, logical reasoning and fast simple heuristics, but the ability to switch between the two that can help the creative thought process. When the deadline for the romcom script roles around you'll have to tap into faster thinking processes. 

Will the project of understanding the underlying cognitive psychology of creativity effectively undermine the existence of creativity itself? I don't think so. The technological, social and ecological sands shift beneath our feet, and even when the process of creative thinking is understood, this process will still have to be applied to novel problems requiring different solutions-and of course the process itself may need to be tweaked in future. Perhaps the romcom will be replaced by a greater form of light romantic titillation, and new tropes will have to be negotiated. (If you didn't get it, the answer is TREE-or at least TREE is one possible answer).

Allen, Andrew P., and Kevin E. Thomas. (2011). "A dual process account of creative thinking." Creativity Research Journal 23(2), 109-118.