I was interested in Bracha et al's postulation that agoraphobia might be a result of evolutionary bias towards safety-seeking among plain-living descendants. I am keen on evolutionary explanations of psychiatric phenomena, despite the fact that they cannot be proved, because they make so much sense to patients. They also allow a different perspective on distressing difficulties, even suggesting some benefit in what had previously been experienced as purely negative phenomena – for example, anxiety conferring a safety advantage in past millennia.

However, I am not so convinced by the explanation given. Many of the patients I see with agoraphobia are most phobic not about open spaces, but about places where they might be seen by others to ‘embarrass themselves’, usually by vomiting, fainting, or screaming out loud. Their over-whelming desire to return home seems to be as much about being hidden from others of the same species as about safety from predators. The explanation I favour is that signs of illness would possibly result in, at best, being excluded from the tribe, and, at worst, being killed and disposed of, both because of the risk of infecting or damaging the rest of the tribe. This is also, of course, related to past and present stigma and understanding of mental illness and unusual phenomena.

My patients have found this a very helpful, rational explanation which has helped them to start making sense of that feels like irrational, uncontrollable behaviour. I will now also include Bracha et al's explanation and see which has more face validity.