Read other letters about this article
Comprehensive Counseling Associates, where Duley conducted group therapy sessions, specializes in ADD and depression - based on his daughter's clinical depression, it's not much of a stretch to guess this is why Ivins attended.
CCA has locations conveniently close to Ft. Detrick. It's chief psychiatrist/practice owner is Dr. Allan Levy, about whom I wasn't able to learn much.
Even for someone of Ivins' generation, receiving vanilla porn at a po box under an assumed name seems unusual. This is pure, unadulterated speculation, but I am going to venture a wild, unsubstantiated guess the porn wasn't so vanilla - if it was wildly kinky or gay (or worst of all, wild gay kink), this would certainly have been a source of psychological conflict/depression in someone with a deep investment in being publicly straight. It would also have meant a deeper, darker secret for the FBI to exploit if in fact Ivins was set up.
I have wondered why, if Ivins was innocent and simply being harassed, he didn't leave some clear statement for his friends and family protesting his innocence, even if he was at his wits' end. Having a secret side he was ashamed of might explain that.
PS: I know the "closeted gay" argument would be much more convincing if Ivins was a Republican, but you work with what you've got.