Tom looks demented.

I think Tom is demented.

Your impertinent attempts at national self-humilitiation have the vagary of a demented maniac, provide you with no condescension but accumulate contempt in the eyes of others and your total worthlessness is congruentially equivallent to your repugnantly low grammatic skills.

You're demented.

She's demented.

Dementia ran in Yanni's family.

Being unable to detect sarcasm is a warning sign for frontotemporal dementia.

It is very unpleasant to watch how my aunt's dementia keeps getting worse every month.

Tom is demented.

Experts already know that years of loneliness or feelings of isolation can lead to anxiety, depression and dementia in adults.