Life threatening neurologic emergency associated with the use of<unk>  agents
Can occur with single dose, increasing dose, or same dose as usual 
Most often seen with "typical" high potency antipsychotics (haloperidol)
also occurs with newer "atypicals" (risperidone, olanzapine)
antiemetics (metoclopramide, promethazine)
withdrawal of anti-Parkinson medication
Develops over 1-3 days
Majority of deaths occur from complications of muscle rigidity
Mortality rates up to 5 to 20% 
Can occur with single dose, increasing dose, or same dose as usual 
Most often seen with "typical" high potency antipsychotics (haloperidol)
also occurs with newer "atypicals" (risperidone, olanzapine)
antiemetics (metoclopramide, promethazine)
withdrawal of anti-Parkinson medication
also occurs with newer "atypicals" (risperidone, olanzapine)
antiemetics (metoclopramide, promethazine)
withdrawal of anti-Parkinson medication
Neuroleptic malignant syndrome
Serotonin Syndrome
Limbic encephalitis
Serotonin syndrome more likely to have hyperreflexia, myoclonus, ataxia, nausea and vomiting, diarrhea
Osmotic demyelination syndrome
Rigidity and hyperthermia, if present, is less severe than in NMS; more commonly presents with clonus and hyperreflexia
Posterior reversible encephalopathy syndrome
Malignant Hyperthermia