What are the five levels of impaired consciousness?
Nov 17, 2025
Source: Cainiu Health
Dr. Zhang Baohua
Introduction
The five levels of impaired consciousness generally include somnolence, confusion, stupor, delirium, and coma. Somnolence is the mildest form of impaired consciousness, in which the patient spends most of the time in sleep but can be awakened by external stimuli such as sound or light. Once awakened, the patient can briefly answer simple questions and cooperate with basic tasks, but quickly falls back asleep once the stimulus is removed.
There are five levels of impaired consciousness, generally including drowsiness, confusion, somnolence, delirium, and coma. The specific details are as follows:
1. Drowsiness: This is the mildest form of impaired consciousness. The patient spends most of the time in sleep but can be awakened by external stimuli such as sound or light. Once awakened, they can briefly answer simple questions and cooperate with basic tasks, but quickly fall back asleep once the stimulus stops. They can only maintain basic physiological needs during daily activities.
2. Confusion: The patient exhibits significant disorientation regarding time, place, and people, and cannot accurately recognize their surroundings. Mood swings are prominent—sudden agitation, anxiety, or apathy may occur. Attention to the environment decreases, making coherent thinking and communication difficult.
3. Somnolence: The patient can only be awakened by strong stimuli, such as loud shouting or pressing on sensitive areas of the body. After awakening, responses are sluggish, speech is unclear and illogical, and the patient cannot fully cooperate with physical tasks. Once stimulation ceases, they immediately return to deep sleep and show minimal response to environmental changes.
4. Delirium: Patients often display restlessness, hallucinations, and incoherent speech. Their perception of the surrounding environment is severely distorted—for example, mistaking ordinary objects for dangerous items. Symptoms may fluctuate, worsening alternately during day and night. Some patients may also exhibit uncontrolled behaviors and are difficult to guide or redirect.
5. Coma: This is the most severe level of impaired consciousness. The patient cannot be awakened regardless of how intense the stimulation is, shows no spontaneous movement, and does not respond to any commands. Some patients may also present abnormal vital signs such as irregular breathing or heartbeat, along with obvious dysfunction of bodily systems, requiring urgent medical intervention.
If someone is observed exhibiting any of the above signs of impaired consciousness, medical personnel should be contacted immediately to prevent delays in treatment. While awaiting medical care, closely monitor the patient’s condition, ensure their airway remains clear and the environment is safe, and take precautions to prevent accidents.
