Trevor Robbins: When does OCD appear?

In this edition of Titans of Science, Chris Smith chats to Cambridge neuroscientist, and expert on OCD, Trevor Robbins...

Chris - When do you think it starts? Have you got evidence that even youngsters have got this but it doesn't manifest in a way that would be visible to their parents, their friends and so on? And it's only as they become adults it gets worse? Or is it that you're fine until you're in your mid twenties, thirties and then you've got a problem?

Trevor - It can occur quite pretty early on, in four and five year olds, and some parents I know have been concerned about that. Now it's really important that it's detected early because I think there's evidence that the longer it's untreated, the worse it gets. This is a real problem because it's very often not picked up until adolescence or even in adulthood. Very interestingly, sometimes you have adult patients who suddenly say, I've got OCD, and you interview them and you realise actually they had problems earlier on, but they didn't surface, they weren't referred to the appropriate clinicians, and so it festered and became full-blown perhaps as a consequence of some experience.

Chris - To what extent are all of us able to have these symptoms? Because I go around people's houses, for example, and I might see that all the CDs are in alphabetical order. The pencils will be on the side in a very specific way. The books will be nicely organised on the bookshelf. There's an innate human tendency towards being organised, isn't there? So to what extent is OCD just a manifestation of this but taken to extremes and is it therefore just a variant of normal?

Trevor - It's an extreme variant of normal. It's a very maladaptive, disruptive version of normal. But I think this is correct. Our hypothesis is that there is this general trait, if you like, which we can call compulsivity. And actually there are questionnaires, you can measure yourself on a compulsivity scale, Chris, and see what your score is. I think it does begin by looking at your overall map of activities. Suppose you've got hobbies, for example, stamp collecting or something like that, and you spend most of your waking hours stamp collecting. Well, that's probably okay. It's fairly adaptive and quite normal. But then if it starts intruding into other behaviours like going out and getting your shopping or even going to work, then you realise you've got a problem. Now, let's go back to something a little more obvious, like internet behaviour for example, going on the web and gaming, gambling behaviours, dare I say porn related behaviours, these are potentially serious disorders when carried to extreme, but of course we have most of these tendencies ourselves initially in the way that we organise our time.

Chris - Is there a genetic element to it? If this is a wiring thing and the brain wires itself up following instructions and recipes from our genetic code, does this therefore run in families?

Trevor - Well, let's begin with OCD. OCD certainly runs in families and there is a genetic basis. We don't know as much about the genetic basis as we do for something like schizophrenia. One of the problems in general with these psychiatric disorders is that they probably have many genes of quite small effect. You can't really talk about a single gene as you can in some diseases like Huntington's. Each of these genes, it's like a hand of cards and together they produce this behaviour which makes it particularly hard to study actually.

Chris - Presumably it's also hard to study because if you grow up in a household where people are behaving in a certain way, you've got to disentangle children copying their parents away from something they're innately compelled to do?

Trevor - Precisely. We've done a lot of studies where we've studied OCD patients and their first degree relatives and you know what? Their first degree relatives tend to be a bit cognitively inflexible and a bit disinhibited. And even the first degree relatives may have some small brain changes, which may be more pronounced in the patients, but they're in the same direction. I definitely think that there's a family basis of this, but as you say, teasing apart the genetic part from the environmental part is tricky. I think both are probably important.

Chris - If we've got some genetic leads we can follow, we've got some magnetic resonance imaging leads we can follow, we can begin to look at mechanisms, and if you've got mechanisms you can begin to think about how we put things right. What is emerging in terms of the best way to manage these sorts of conditions?

Trevor - Let's talk a little bit about genetics again. Some of the genes associated with OCD seem to be related to a chemical messenger in the brain called glutamate. Glutamate is very important for the excitatory part of your activity in areas like the frontal lobes. You can actually measure glutamate and its partner GABA, which is its opposing inhibitory influence, using a technique called magnetic resonance spectroscopy. That's simply based on measuring with a huge magnet the way that chemicals resonate under that magnet. You can then measure actually how much you've got of each of these neurochemical metabolites if you like. Now we did a study recently using the seven Tesla magnet here and showed that patients with OCD have an increased level of glutamate in part of the frontal lobes. And moreover, this increased level correlated with their symptom severity. It correlated with a questionnaire which measured how compulsive you are. We even found in healthy volunteers as control subjects a similar result, even though they're not as compulsive as OCD patients. And we also showed with an experimental test that measures the bias to habits, a relationship with this increased glutamate level. So we would argue that one thing one needs to do is to improve this balance of glutamate and its partner GABA in the frontal lobe, and there may be pharmacological ways of doing that,

Chris - Have people not also experimented with electrical stimulation where you put deep electrodes into the brain and use that to drive different patterns of activity. That seems to give some people relief?

Trevor - Absolutely. Neurosurgeons actually still perform what we call cingulotomies, which are removing a bit of this hyperactive region of the frontal lobes, and it actually works. It's the only bit of psychosurgery that's ever seemed to work. However, there's a gentler way of doing that, as you've mentioned, using so-called deep brain stimulation. Very fine electrodes are put into the brain - as used in Parkinson's disease a lot to unblock the system - and there's a similar rationale with OCD and it works. It can only be given to patients where nothing else works: cognitive therapy, drugs. They're desperate because they're performing rituals most of the time. We were lucky enough to be in the first UK study recently with Queen Square London where some patients experienced an enormous relief of their symptoms. I think one lady was confined to her house with her OCD, but after deep brain stimulation she was able to go out and interact socially and even get a new boyfriend and go on holiday. That's what I call a real clinical effect.