Drunk last night and can’t remember anything now?
What are alcohol blackouts?
Alcohol blackouts are periods of lost memory during times of alcohol intoxication. Although the terms blacking out and passing out are often interchanged and confused, passing out actually refers to a loss of consciousness, while people who later blackout on memories were fully conscious and often carried out complex events during the time of their memory blackout.
You can’t blackout on memories formed while unconscious…there aren’t any to miss!
No one would know to look at an intoxicated person during a time of memory blackout that he or she was in fact in a memory blackout.
Fragmentary and Complete Blackouts
There are 2 types of alcohol induced blackouts – fragmentary and total. People who have experienced a fragmentary blackout may not recall the events of a period of intoxication until they are reminded or cued about them.
- “Remember jumping into the pool last night with your clothes on?”
- “Oh my, I’m starting to remember that now…I can’t believe I did that!”
People who have experienced a total blackout will not remember, even with memory cues, any of the events that occurred during the period of the memory blackout.
- “Remember jumping into the pool with your clothes on?”
- “What pool?”
Blackouts can last for hours or even days. Memory blackouts do not affect memories formed prior to the onset of drunkenness.
Why Does Alcohol Cause Blackouts?
Alcohol is a systematic drug that affects nearly all systems of the brain. The hippocampus, a primary area of memory formation and retrieval, is no exception.
What seems to happen is that alcohol disrupts the brain’s ability to consolidate short term memories and process them into long term memories.
We have 3 types of memory.
- Process or immediate memory
- Short term memory
- Long term memory
Process memory lasts only a few seconds, and allows us to perform daily tasks with ease.
Short term memories are slightly more significant, and are stored in the brain for a few minutes.
Short term memories that are very significant, and that are “practiced or thought about quite a lot” are moved into long term storage.
Alcohol seems to block the brain’s ability to take salient short term memories and move them into long term storage.
What this means is that since short term memory storage is unaffected, an intoxicated person can maintain a conversation as per normal (Where the flow of the conversation rarely demands that you recall facts for more than a few minutes) but if asked to recall events of an hour before, or the night before, the intoxicated person would have much more trouble.
Alcohol affects the nerve cells in the brain. This means it interferes with how the cells function and how the brain communicates with all other parts of the body.
Alcohol is a central nervous system depressant. The central nervous system includes the brain, the spinal cord and the nerves originating from the spinal cord. Intoxication occurs when alcohol acts on the central nervous system, affecting emotional and sensory function, judgment, memory and learning ability.
Different parts of the brain control different processes. Alcohol affects each of these areasat varying rates and times; as BAC increases, the effects get more pronounced.
The cerebral cortex processes information from your senses; it also controls how you think and the movement of your muscles. When alcohol affects the cerebral cortex, you take longer to process information from your senses, become less inhibited and don’t think as clearly.
The limbic system is the part of the brain that controls memory and your emotions. When it is affected by alcohol, your emotions become exaggerated – for example, you could get more giddy, sad, or upset – and you start to forget things.
The cerebellum coordinates fine muscle movements, including the muscles that help you keep your balance. As alcohol affects the cerebellum, you can become shaky and uncoordinated and unsteady on your feet.
The hypothalamus controls a number of functions, including sexual arousal and performance. When it is affected by alcohol, sexual arousal increases, but performance decreases. The hypothalamus also coordinates hormone production in the pituitary gland. One of these hormones is anti-diuretic hormone (ADH), which works to reabsorb water in the kidneys. Alcohol restricts production of ADH, which means the kidneys produce more urine.
The brain stem controls automatic body functions such as breathing, heart rate and consciousness. When alcohol reaches the brain stem, you become sleepy and, depending on how much alcohol you drink, you may even lose consciousness. As the concentration of alcohol in your blood increases, it may affect your heart rate, breathing and consciousness and can even lead to death.