A state of sketch that occurs when a person displays iffy behavior, either because (s)he is just a mess or because (s)he is under or has been under the influence or drugs and/or alcohol, then forgets said dubious behavior altogether. (S)he will probably then use this forgetfulness to excuse further bad behavior that is a result of the initial iffiness (sketch).
Damn, dude, I'm sorry I slept with your girlfriend. I had a crazy night out and my sketchzeimers must've kicked in. It happens when I don't take my meds.
Geez, bro, what's up with you? You asked me to change the date of the photo shoot to accommodate YOUR schedule and when I remind you of it, you have no clue what I'm talking about. You have a serious case of sketchzeimers,