I myself have scoliosis and had two major depression (the one had nothing to do with the other). I don't think you can call scoliosis a desease, it's more a condition; it's a deformation of your spine and causes a lot of back pain. Standing up for more than an hour is realy painfull, so I can imagine what Anastasia went through (considering all those ceremonies).
I am 23 now (the age Olga was when murdered). As for bi-polar, there have to be periods of extreme happiness following periods of extreme depression. I don't think Olga had bipolar disorder, just depression. Or does anyone know of her having manic periods? Being the oldest and brightest of her siblings, one can understand why she was more vulnerable for depression. The moods I can understand, I myself went through them. Being depressed you try to hide it from your family and the people close to you, so not to cause them more pain (and Olga's parents had enough of their own problems with the war, the hospital, Alexey,...) So the best thing you can do is to put on a happy face, but that doesn't realy work when you're actualy dying fom the inside, so you make a bigger efford. But it never works, cause you still feel awfull. To the outside world it looks like you have moodswings, but you're just trying to live trough the day and to please the people you love. The worst thing about depression is that you feel guilty you are depressed. And when you think about Olga who spend whole days with realy sick, invalid soldiers, her guilt must have been immense. Here were lying hundreds of brave young man, in great pain, and you are young, have everything and still feel so terrible. The feeling of guilt eats you up from the inside. No wonder Olga had a nervous breakdown.
It's realy hard to explain what I'm trying to say (it's always hard to put in words what you feel) but I hope some of you do understand what I'm trying to say.