Well, I didn't put this Dwarf in suicide squad. Legendary clothier tough on stress... What a painful loss it would be. Though I have sent stressed Dwarves with good stress resistance under atom smasher before. I only disabled all hauling and construction on this Dwarf, so she could work exclusively on her needs and get her focus up. Miracle happened. After 1 month the red arrow of stress went away. Thanks the higher focus alone.
Yellow arrow by itself seems to be quite harmless.
Low focus is not causing additional stress, but it seems low focus somehow prevents sufficient stress dissipation.
Low stress tolerance somehow causes existing stress to keep excessively growing. Even, if Dwarf has needs satisfied and is focused.
Mulling over stressful things maybe is somehow responsible there with these continuous stress gains? How you make Dwarf to mull on 8 stronger things, then the stress-factor?
Red arrow combined with a stress/depression weak Dwarf means, "death help", is the only cure available.
Red arrow combined with stress/depression strong Dwarf means, you need to get them into a better focus. Problem is, what if you can't yet without special workshops and special comfort food and other specials, which you just can't care about without better automation system in?
IMHO rain gets way too much to play with Dwarves. I have seen Dwarves going crazy amass because of some death body's sight. Rain drops of water ain't bloodied and cut into pieces dead body of some sentient being. This rain sensitivity in Dwarves seems to be somehow greatly overplayed. Dwarves should be more tough with rain, then they are to sun (the cave adaptation!), but it is not so.
Cave adaptation is one mechanism of copying with neural disorder. Why don't we have something alike for dead bodies, rain, rotting cloths and so on. The more you get the rain, less you care about rain. In time you can live in rain without noticing the rain, like when cave adaptation goes away, because you're living on surface and not in cave.