This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Dementia Due to Metabolic Causes, Subject name: Psychiatry
Clouding of consciousness is seen in: 
Select and explain. 
A. Dementia, B. Delirium, C. Schizophrenia, D. Depression
B: Delirium
Answer: B: Delirium 
Explanation: Ans. (b) DeliriumRef.: Harrison 19th ed. /166DELIRIUM* It is characterized by global impairment of consciousness (clouding of consciousness), resulting in reduced levels of alertness, attention & perception of environment along with acute onset of fluctuating cognitive impairment.* It is the commonest organic mental disorderClinical Features & Diagnosis* Global impairment of consciousness & attention is the hallmark/cardinal feature of Delirium. It manifests as:# Diminished ability to focus, sustain or shift attention.# Reduced levels of alertness, attention, and perception of environment.# Drowsiness (mental slowness), distractibility & disorientation.* Global impairment of cognition is manifested as:# Disorientation (in time, place and person)# Disturbance of immediate & recent memory# Remote memory is intact.