Drugs (most common cause) - alcohol/drug intoxication or withdrawal
Metabolic/endocrine - hypoglycemia, thyrotoxicosis
Neuro - trauma, tumor, stroke, seizure, ICH, meningitis/encephalitis
Other - hypoxia, systemic infection
Psych - psychosis, schizophrenia, mania
*Always consider an organic etiology first. An organic etiology is more likely if: sudden onset, age >40 with no psych history, abnormal vitals or exam.
Your workup should be guided by the patient's H&P and any collateral information you have gathered. All patients should get an ECG.