Insanity

Hakuba does often wonder if his paranoia borders on insanity. He has a ridiculous amount of contingencies set up in the event of his untimely demise, most of which involves delivering information about his various cases into hands that he believes are capable of handling them. Sometimes, as he writes the letters that he sets aside for this purpose, he has to stop and ask himself if he is, in fact, insane. 

Pawns

One of the reasons why my Hakuba hates the Spider that I’ve written in his backstory is that he uses a combination of white widow cocaine and a drug called scopolamine on his targets and bystanders… This allows him to produce those illusions, each tailored to a person’s individual fears (think Batman’s Scarecrow), and makes them very willing volunteers for whatever Spider wants them to do. For the criminals that he assassinates, it usually involves forcing them to play out their worst nightmare before they die. Since Hakuba’s not really a target, he’s only seen glimpses of this, but both times (especially the first), left him shattered, angry, and terrified.  

Delirious

The nightmares will sometimes have this effect. It doesn’t happen often, but the nightmares, or something will trigger his PTSD and suddenly the eidetic memory kicks in and Hakuba turns from a professional, level-headed detective to a crying mess on the floor, or scrambling to escape. Just the right combination of triggers and you can have him screaming bloody murder and stuck reliving the past until he’s snapped out of it.