WARNING: Possible mentions of psychological conditions that are serious enough to warrant a warning. If anyone feels it's becoming too heavy, do tell.
So I was thinking about the flaws that GD's aptitudes were meant to remove, and by extention the actions or wishes they were meant to stop them from. So a bit more serious thing occured to me:
If one is a Candor GD, would that mean it'd be hard or impossible for them to develop the disorder of pathological lying? Because their aptitude makes it very hard for them to want to lie. The experiment's goal was to remove negative behaviors, so it's safe to assume many GD's are indeed deprived of them on an involuntary level at least up to a point, it's more than what they just refuse to do.
By the same logic, an Erudite would be little likely to develop amnesia, DID, or anything else that makes them forget, be unaware or incapable of remembering. Excluding things that happen for a physical influence, only psychical ones. If their first instinct is to pursue knowledge, discover and remember, it's hard for their subconsciousness to cause something that makes them unable to- because subconsciousness is the part that wants things, and they are made to want good mental functioning.
For Abnegation, it would be narcissistic disorder, borderline syndrome (as it's focused on how others feel about us, and they instinctively disregard themselves), maybe even ADHD, as their aptitude makes them focused on others.
Amity- depression, anger issues, sadism, perhaps also borderline, anything that is rooted in negativity towards other people or life.
And Dauntless: conditions that develop because our subconsciousness wants to escape something terrifying or unpleasant, our because we already gave in to fear, such as phobias (they are even obligated to overcome them), paranoia, and maybe also DID in the sense of it not being instinctive for them to forget and move away from something personally attacking them.
DISCLAIMERS:
I'm no expert, only an amateur interested in psychology.
This is the neurological side of things, but we've already deduced here one's personality can at times overcome that.
I'm not saying people with these conditions have them for a lack of a virtue, on the contrary, because faction's main virtues and flaws are artificial, that's why it's a problem, it would mean artificially treating these conditions. In fact they may even have them but their DNA wouldn't allow them to freely show. I was also going to talk about conditions aptitude makes more likely, but it's too long already. Neither GD's nor people with these conditions are in any way worse due to it, that's not my message.
I realize it's a heavy topic, but decided to post and see how it goes.