How could we reframe that question, problem-definition, or decision?

FORBES: If You Knew This, You'd Be Rich By Now

But part of the problem with the definition - I mean, as an example - is that if you look at Mars - if Mars - if we discovered a Mars-sized object out beyond the orbit of Pluto, it couldn't be a planet, because over the age of the solar system it wouldn't have time to clear its orbit.

NPR: Astronomers Prepare to Fight Pluto Demotion

The problem with that definition, of course, is that not just anybody can measure it -- since most of us don't have an International Prototype Kilogram laying around, especially since every time the thing is picked up a few atoms rub off of it making it a little bit lighter.

ENGADGET: blogger-avatar

In terms of your question: If the person you are thinking of was completely normal before the head trauma, had serious head trauma and has been out of touch with reality ever since -- which is really the definition of psychosis -- then it is extremely likely that the head trauma is the cause of the problem.

CNN: Can traumatic brain injury trigger mental health issues?