Psychology: Brain injuries changing personality?

From a recent letter to friends:

I recently put up a story on Phineas Gage (the famous (probably fake) psychopath. That was the guy who - as a boastful atheist religion prof proclaimed to me - was the subject of hundreds of textbook entries, and therefore the story must be true. Here's a typical government-funded legend that prompted the discussion.)

No, not true, just widely reported.

For what it is worth, I am doubtful that brain injuries would normally simply change a personality entirely. The idea is long overdue for questioning.

For one thing, personality is created by many factors - gender and birth order, for example - factors that will not change due to a brain injury. It would be difficult for a brain injury to merely overrule all such factors.

Re gender and birth order: Men tend to be more dominant than women, but in a large family eldest sister may tend to be more dominant than youngest brother, the baby of the whole family.

A random brain injury is not a guided intervention. It may or may not affect personality.

I am hardly surprised to learn that the brain injured are subject to sudden, "inexplicable" rages.

But so are many other people who find themselves undergoing a disaster they can't easily understand (physical disfigurements or dismemberments or losses of function, for example).

They soon discover that no one really has answers that solve their problems. They are subject to many boring, ridiculous, and humiliating problems.

That's just what happens when you survive a catastrophic accident.

Of course there may be factors related to a specific brain injury that could alter personality. I don't deny that; I simply say that these factors should be much more carefully delineated and qualified than they have been in the past.