Vascular dementia

Multi-infarct

Diffuse white matter disease (Binswanger’s)

PDD/LBD spectrum

Drug/medication intoxication

Limbic-predominant age-related TDP-43 encephalopathy

Vitamin deficiencies

Thiamine (B1): Wernicke’s encephalopathy

B12 (subacute combined degeneration)

Nicotinic acid (pellagra)

Endocrine and other organ failure

Hypothyroidism

Adrenal insufficiency and Cushing’s syndrome

Hypo- and hyperparathyroidism

Renal failure

Liver failure

Pulmonary failure

Chronic infections

HIV

Neurosyphilis

Papovavirus (JC virus) (progressive multifocal leukoencephalopathy)

Tuberculosis, fungal, and protozoal

Whipple’s disease

Head trauma and diffuse brain damage

Chronic traumatic encephalopathy

Chronic subdural hematoma

Postanoxia

Postencephalitis

Normal-pressure hydrocephalus

Intracranial hypotension

Neoplastic

Primary brain tumor

Metastatic brain tumor

Autoimmune (paraneoplastic) encephalitis

Drug, medication, and narcotic poisoning

Heavy metal intoxication

Organic toxins

Psychiatric

Depression (pseudodementia)

Schizophrenia

Conversion disorder

Degenerative disorders

Huntington’s disease

Multisystem atrophy

Hereditary ataxias (some forms)

Frontotemporal lobar degeneration spectrum

Multiple sclerosis

Adult Down’s syndrome with Alzheimer’s disease

ALS-parkinsonism-dementia complex of Guam

Prion (Creutzfeldt-Jakob and Gerstmann-Sträussler-Scheinker diseases)

Miscellaneous

Sarcoidosis

Vasculitis

CADASIL, etc.

Acute intermittent porphyria

Recurrent nonconvulsive seizures

Additional conditions in children or adolescents

Pantothenate kinase–associated neurodegeneration

Subacute sclerosing panencephalitis