Neurologic Cerebrovascular disorder (hemorrhage, infarction) Head trauma (concussion, posttraumatic hematoma) Epilepsy (especially complex partial seizures) Narcolepsy Brain neoplasms (primary or metastatic) Normal-pressure hydrocephalus Multiple sclerosis Metachromatic leukodystrophy Migraine Autoimmune encephalitis (e.g., NMDA receptor) Endocrine Hypothyroidism Hyperthyroidism Hypoadrenalism Hyperadrenalism Hypoparathyroidism Hyperparathyroidism Hypoglycemia Hyperglycemia Diabetes mellitus Panhypopituitarism Pheochromocytoma Gonadotropic hormonal disturbances Pregnancy Metabolic and systemic Toxic Intoxication or withdrawal associated with drug or alcohol abuse Adverse effects of prescribed and over-the-counter medications Environmental toxins (volatile hydrocarbons, heavy metals, carbon monoxide, organophosphates) Nutritional Vitamin B12 deficiency (pernicious anemia) Nicotinic acid deficiency (pellagra) Folate deficiency (megaloblastic anemia) Thiamine deficiency (Wernicke– Korsakoff syndrome) Trace metal deficiency (zinc, magnesium) Nonspecific malnutrition and dehydration Celiac disease Infectious AIDS Viral meningitides and encephalitides (e.g., herpes simplex) Brain abscess Viral hepatitis Infectious mononucleosis Tuberculosis