At the risk of repeating myself: OCD is a neurological illness. That is something I find important to emphasize. OCD and other anxiety and mood disorders are still viewed by many to be the product of a ‘warped mind’, something immaterial. Something that cannot be seen, not even if you were to lift the skull of a person; a figment of the imagination. Perhaps even something simulated by persons who want to exempt themselves from society, in one way or another. I happen to know of politicians who really use such an opinion to win over voters who are at best ignorant, and at worst really malicious and greedy (after all: treatment and benefits for patients with mental problems cost taxpayers’ money).
People can’t simulate a disorder like OCD. No one ever can be always ‘on guard’, and continuously monitor themselves as to their ‘performance’ of the role of patient.
Moreover, OCD does have a biological substrate, or better: it does have several biological substrates in the brain; areas that are affected, that are associated with the disorder. Note the use of the word ‘associated’, it’s important. Scientists use it to make clear that one state of things is somehow occurring together with another state of affairs, without assuming causality in one direction or another. Something that co-occurs with something else can be the cause of that other phenomenon; or it can be the consequence; or both can be related to a third and as yet unknown, unidentified substrate or state.
Many findings in research are suggestive; if a certain area of the brain is known to be involved in the processing of fear, and we present a photo of a fearful event to a test person; and if that area in our subject gets very active in our laboratory, as seen on some scanning picture – then it is highly tempting to jot down: fearful photo causes hyperactivity in this or that area.
That is not totally wrong, but it’s overenthusiastic in its claim. We don’t know all the variables. We don’t know whether the subject will react that way with only this type of photo, or with just any photo (perhaps the person has a hitherto unknown disorder called ‘photophobia’…). Or he/she is very afraid of having a scan made of the brain. Or the researcher just brings about a lot of fear after a certain amount of time. Or second, third, fourth as yet unknown brain areas are the true cause of our ‘suspect’ area showing a lot of activity.
And that is why we must be cautious with assuming direct causality. Therefore, we use terms like ‘association’, or ‘correlation’. Yes, we keep our options open that way, but it’s not because we are cowards. We are careful.
Now, what do we know about brain areas (also called: ‘regions of interest’, ROIs) potentially involved in OCD? A lot, in fact. What’s more: despite all due caution we have to observe, the actual function of several brain areas, and the symptoms observed in OCD lend credibility to what we can see in scientific assessments. The results of these are related to:
- the metabolism of nerve cells
- the viability of nerve cells
- the activity in a number of ROIs
- the size of some ROIs
- the shape of some ROIs
- the connections between different ROIs
- the actual parts that ROIs play in complex circuits
For now, I will leave you with some posh names to remember: major brain ‘players’ in OCD are:
- the cortex
- the basal ganglia
- the thalamus
- the insula
- the corpus callosum
- the amygdala
- the cerebellum
Most likely, there are more ROIs. But this list will suffice for now.