Hey! Wait a minute! It's a long ride from lack of focus, forgetting, etc. to "failing mentally." That's not happening to anyone here, yet. There are only two choices---ever. Suck it up or or give it up. The latter is a pretty shetty option.
We identify and address problems, succesfully, all day long, every day. We're just not so good at it when the problem is our own.
The definition of a mental failure could be anything from the small, like forgetting to close the lid on the toilet, to the large, like the Sheen diatribes.
Don't read too far into it by the sound or perhaps connotation of the word "failure".
Choose another word if it sounds more polite if not less accurate.
Ongoing, intermittent mental lapse.
Occasional and increasing mental pauses.
Periodic persistent brain farts.
