It is possible to rationally realize that dying would have negative utility, even failing to take into account fear of death.
In general, evolution tends to produce redundant systems for reproduction-critical activities.
I would say yes, often times depression manifests itself not as a feeling of fear or dread but as apathy. See for example Hugh Laurie's personal life [1,2] or Nine Inch Nails' Everyday is Exactly the Same[3] which captures that exact feeling. Or of course the wonderful Hyperbole and a Half's account of depression[4], especially the second part makes the point that depression at its worst is a void. No positive feelings, but also no negative ones.
Now I made myself sad^H^H^H apathetic going through those sources. Why does Trent Reznor have to be so good at projecting?
As for the anxiety bit (anxiety and depression are to completely different things), the article mentions her response to having her blood-co2 levels elevated, which seems to me to be a standard anxiety response. A feeling of restlessness and dread.
[1] http://en.wikipedia.org/wiki/Hugh_Laurie#Personal_Life [2] http://www.dailymail.co.uk/tvshowbiz/article-2316880/Playing... (I know, I know, Daily mail but the quotes are worth it) [3]https://www.youtube.com/watch?v=-Aj9_8t1eQc [4] http://hyperboleandahalf.blogspot.nl/2011/10/adventures-in-d...
> I wonder if you can be truly depressed if you don't fear anything?
In the podcast, she does describe herself to be happy 9 out of 10 times.
> Or does her lack of fear not encompass anxiety?
I asked someone who had met her in person a similar question: https://news.ycombinator.com/item?id=8927905
What stops her from killing herself out of curiosity ?
Would she make a better or worse soldier ?
I wish this woman did an AMA.