Sandman
For instance, when his wife is angry with him, or nags about something (as perceived by him), he can shut her out and then come online and drag up an old topic just to vent his frustration. I wouldn't call it therapy because it doesn't really result in anything productive for him, but I think that deep inside, that is what he's after - closure on the frustration, closure on that nagging feeling inside him where everyone is his enemy.

Slimer
If he's a Cancer (and he is), he is a homebody and definitely has a shy nature.

Anxiety is stretching it though. I just get the impression that he never bothered to come out of his shell as a child. I just think he uses anxiety as a convenient excuse for his flaws and the fact that he would associate it with post-traumatic stress disorder like he did today, which is nothing like it, shows that he is constantly looking for an external explanation. At best, he is a coward. Not mentally ill, just a coward.