...together with Giuseppe Berto's Il male oscuro and a segment of Marjane Satrapi's Persepolis (I think my most vivid memory of it is actually of a deleted scene from the animated movie, but surely it's in the comic book too).

In all three cases, the distinguishing factor is an appropriate amount of self-irony. In Persepolis, there is just enough of that for the reader to sympathize with the protagonist while still taking her seriously. In Il male oscuro, it seems to be the very way in which the author allows himself to disclose the character's (and maybe his own) darker thought patterns. In Anxietyland, it is presented as the author's own coping strategy.

On the one hand, this provides a dose of entertainment that certainly helps readers, especially those who cannot directly relate to these levels of psychological suffering, stay open and empathize. On the other, I do not think it is the (only) reason why it is there. It seems to me that irony belongs in a lot of moments of mental distress, both as one of the sufferer's natural self-defense mechanisms and as their close ones' intuitive way to try and de-escalate the situation. Because of this, these books primarily strike me as authentic.