A certian kind of hang over that involves involentary giggling and incessant laughter over the the most mundane matters. Sometimes more fun than the drunk you experienced the night before.
*over constant laughing* "Shit! We've got the dementia!"
by Radcliffe March 16, 2007
When you are sick of either three-dimensional or two-dimensional media, so you want to see something different.
Whenever I get dementia, I switch from Super Mario Bros. to Super Mario 64, and when I get sick of both, I crave a fourth-dimensional Mario game, so now I'll have dementia until Nintendo makes that.
by ducus10000 April 9, 2018
"That dimension fever we all have." A joke used at the begging of a video titled "2D to 3D - Scott the Woz" by YouTuber Scott the Woz
Dimensions am I right? I've decided to make a term for that dimension fever we all have from time to time, Dementia!!

Urban Dictionary doesn't know what's about to hit it.

This is the Wikipedia article for puberty
by Yoshomay June 6, 2020
When you get told to go to do a certain task, told about 30 seconds ago. You then walk to the room knowing the task. As soon as you enter the room you instantly forget the task. I have know idea how this happens or if the doors have dark magic or something. But the only logical explaination is that i have dementia.
Timmy: yo tf was i supposed to do again?
by i out pizza'd the hut November 4, 2020
Idk what it means I forgot lol
Dementia (dɪˈmɛnʃə)
by Archi-medes March 13, 2020
It's basically-Wait what was it again?
No guys what was Dementia- Am serious.
by TheGuyThatForgets March 21, 2021
Person 1: " I have dementia."
Person 2: "Wow that sucks! How did you find out?"
Person 1: "I just got told by my doctor, dumbass."
Person 2: "Oh yeah, anything else you want to tell me?"
Person 1: "Oh yeah, I wanted to tell you I had dementia."
by OctopusProbably March 23, 2022