Great thread, sorry to be late to it. 
Scotland is different from England imo because it has a strong and secure sense of its own national identity and history.
The English national identity by contrast is elusive, fragile and easily threatened by outsiders, who threaten to dilute it. MN is fond of denouncing bullies with fragile egos as narcissists, and England is a classic case. We like to pretend that England and Great Britain are coterminous, and we're still dining out on our former imperial glories because it's hard to think what we've done recently that's great. (Ironic, because some of our finest achievements have actually occurred in the latter half of the C20, e.g the NHS, the welfare state... um, OK, that's it actually.) We relive this greatness through occasional ill-conceived military forays and football. We are envious of the sentimental trappings of patriotism that other countries, particularly the US, display, and often try to copy them, with varying degrees of success, e.g. Independence Day, Thanksgiving, that annoying hand-on-heart thing that athletes all seem to do on the Olympic podium nowadays. Our national symbols, the poppy, the flag of St George, and the red nose (let's be fair, we have a GSOH), are typically displayed proudly on our German, Japanese or French cars.
Interestingly, in the local areas that have a strong regional identity (London, Liverpool, Newcastle, Brighton) or a healthy ego (Oxford, Cambridge), the Remain vote was high, as in Scotland.
(I am being only slightly tongue-in-cheek, just to be clear.)
Actually, I do believe that many (most? all?) nations have a psychiatric profile. The US, for example, has paranoid schizophrenia. That may be best kept for another thread though. 