I've said this before, but I feel that stress damage heals too quickly for the guidelines for Fragile Minds. If someone possess you and forces you to brutally murder your best friend, you're looking at potentially 6d6 +2 points of stress damage (2d6 for the magic and 4d6+2 for the act). That's an average of 23 points. If the hero in question had a Wisdom of 12, then he'd need ten minutes per point to recover the first 11 points, then another 12 minutes after that. So he'd feel bad for a couple of hours after which he's no worse for the wear. Note that since this stress damage was inflicted over different rounds (magic then murder) it's unlikely he would have to make a Table of Sproig roll.
I just don't find that relalistic. I'm thinking of creating a Campaign Quality that limits a character's healing to a flat per day like wound points. I was thinking, if you get a good night's sleep, you heal (Wis Mod+1) x Character Level. If you get a full day away from any stress you heal (Wis Mod +3) x Character Level. Other possibilities would be lowering the threshold for Sproig since it prohibits healing until Therapy.