- Exposure to haldol, chlorpromazine, other typical or atypical neruoleptics/anti-psychotics
- More common w/high dose or soon after rx/dose change, but also idiosyncratic→ occurring after years of rx
- Sx progress over several d
- Fluctuating delirium→ aggitated or stupor/alert mutism to coma
- Autonomic instability w/hypertension, tachycardia, tachypnea
- Temp can be > 41.1c
- Mental status on spectrum from agitated to coma
- Generalized lead-pipe type muscular rigidity
- Decreased reflexes