Psychomotor retardation (most common): immobility, mutism, staring, withdrawn, refuse to eat/drink, refusal to follow directions (negativism)
Presents acutely, though precise precipitant (e.g. med change, progression of underlying psychiatric dz) often not clear
Agitated or malignant form (much less common); similar to Neuroleptic-Malignant syndrome; psychomotor agitation, confusion, autonomic instability; w/significant risk morbidity/mortality
Physical Exam Findings
Staring, mutism, rigidity, waxy flexibility
Less commonly posturing, grimacing
Malignant form assoc w/more severe illness: agitation, fever, abnormal pulse and bp