Sickness altering personality temporarily?

I have a few friends (who dont know eachother) who after recovering from a somewhat serious illness and for a few months they seem to have a massive personality change. I wanted to know if anybody has heard of anything like thisSickness altering personality temporarily?
Being ill makes people cranky, especially when they've been sick for awhile and their energies have been sapped. It's also very depressing to be ill. Your friends tend to come around less, and you feel left out. So, yes, it's not unusual to have a change in personality.
Hang in there with your friends, though. When their strength and outlook improve, so will their personality. And they'll love you for putting up with them.
I hope it's a good positive change. Only after an illness does one realize how precious life is. If this isn't the case, perhaps it's all the drugs that have been pumped into their bodies.