Blackouts are medically defined as periods of unconsciousness or memory loss.
Blackouts are medically defined as periods of unconsciousness or memory loss.

Blackouts are medically defined as periods of unconsciousness or memory loss. They may occur because of brain damage, head trauma, excessive alcohol consumption, drugs, or disorders affecting brain function. Fainting, also known as syncope, is used to refer to a blackout. It happens when the brain does not receive enough oxygen supply for a short time due to problems in the regulation of blood pressure or due to cardiac problems. Syncope is the most common cause of the blackout, which comes on suddenly, usually lasts for a short time, and recovers fully. Blackouts can also occur due to epileptic attacks (seizures) and psychogenic reasons, such as stress and anxiety. Blackouts can occur in children and adults. A blackout may occur just once, or it may be recurrent. Blackouts need medical attention to rule out any serious causes. Treatment of blackouts depends on the cause.

What causes blackouts?

Some common causes of blackouts include:

Alcohol-induced blackouts:

Blackouts are often associated with alcohol consumption. Alcohol impairs the ability to form new memories while intoxicated. Two different kinds of blackout can result from drinking alcohol: en bloc (complete) and fragmentary (partial). An individual who experienced partial blackout may recall what happened when prompted by verbal clues. With complete blackout, the memory loss is permanent. It ends when the body absorbs the alcohol, and the brain can form memories again.

Syncope blackouts:

Common faint or vasovagal syncope is the most common cause of the blackout and is mostly experienced by boys and girls in their teenage years. In this condition, there is a disruption in the balance of neurotransmitters that regulate the blood vessels and heart rate as a reaction to stressful or frightening situations. A neutrally mediated syncope is usually benign and does not require further treatment. Cardiac syncope is more serious because it could signal an underlying heart problem, such as hypotension, bradycardia, tachycardia, etc. Cardiac syncope is more serious, and the person may have the risk of cardiac complications or sudden cardiac death without timely intervention.

Epileptic blackouts:

A disturbance of neural activity in the brain can cause an epileptic blackout. The patient may experience a seizure during this blackout. Their muscles may contract and lose consciousness. The tonic-clonic seizure also known as grand mal seizure is the type of seizure that causes an epileptic blackout.

Blackouts can also be caused by other conditions, such as:

What are the signs and symptoms associated with blackouts?

Blackouts may occur with a variety of other symptoms depending on the underlying disease, disorder, or condition. In some cases, blackouts could be a symptom of a life-threatening condition that must be evaluated immediately. If the blackouts recur more often, the patient must seek prompt medical care.

The common symptoms associated with blackouts include:


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Medically Reviewed on 3/11/2021
Morag R. Syncope. Medscape.