demented

Synonyms: bananas bemused crackbrained daft delirious deranged distracted distraught flipped out foolish frenzied fruity hysterical idiotic in the ozone lunatic mad maniac maniacal manic non compos mentis nutty as a fruitcake out of one’s gourd out of one’s tree psycho psychopathic psychotic schitzy schizoid unbalanced unglued unhinged unsound whacko

Antonyms: balanced rational reasonable sane sensible