Here's another connecting piece of information from my old University

2 August 2010 Media Release, University of Otago, New Zealand

Effectively it is thought that severe depressives have a lower ability to detect facial expressions.

But like most research there never seems to be any hypothesis as to why this is so.

So lets kick off...

The inability seems to be like what autistics also have.

But a seemingly obvious hypothesis is that depressives being withdrawn and internally focused have had fewer interactions with others and by relying less on that interaction have less knowledge and awareness of others expressions. Another angle, like the autistics lack of eye contact, is that they simply have not been observing others facial expressions because they have not looked at peoples faces that much.

The issue I see with depressives is that they can mask their condition; their facial expressions do not necessarily represent their state/predisposition relative to the norm. Hence that makes it harder to understand others as they know there own expression is not a true reflection. But the lack of eye contact is because that cannot mask their condition.

An interesting experiment is whether depressives have the ability to sense other depressives more easily. They might not be in tune with normal expressive behaviour the same but I'd say they are acutely aware of similar predispositions.