non compos mentis (adj.)

• abnormal
• brainsick
• crackbrained
• cracked
• crazed
• crazy
• daft
• demented
• deranged
• disoriented
• distraught
• flighty
• insane
• irrational
• loco
• lunatic
• mad
• maddened
• manic
• mazed
• mental
• odd
• off
• queer
• reasonless
• senseless
• sick
• strange
• touched
• unbalanced
• unhinged
• unsettled
• unsound
• wandering
• witless