Amnesia is a form of memory loss.
Some people with amnesia have difficulty forming new memories. Others can’t recall facts or past experiences. People with amnesia usually retain knowledge of their own identity in addition to their motor skills.
Mild memory loss is a normal part of aging. Significant memory loss or the inability to form new memories may indicate the presence of an amnestic disorder.
The primary symptom of amnesia is memory loss or the inability to form new memories. If you have amnesia, you may experience the following:
- difficulty recalling facts, events, places, or specific details (which can range from what you ate this morning to the name of the current president)
- an impaired ability to learn new information
- an inability to recognize locations or faces
- confabulation, in which your brain subconsciously invents false memories to fill in memory gaps
You’ll still retain your motor skills, such as your ability to walk, as well as fluency in any languages you speak.
There are multiple types of amnesia, including the following:
When you have retrograde amnesia, you lose existing, previously made memories.
This type of amnesia tends to affect recently formed memories first. Older memories, such as memories from childhood, are usually affected more slowly.
Conditions such as dementia cause gradual retrograde amnesia.
When you have anterograde amnesia, you can’t form new memories.
This effect can be temporary. For example, you can experience it during a blackout caused by too much alcohol.
It can also be permanent. You can experience it if the area of your brain known as the hippocampus is damaged. Your hippocampus plays an important role in forming memories.
Transient global amnesia (TGA)
Transient global amnesia (TGA) is a poorly understood condition. If you develop it, you’ll experience confusion or agitation that comes and goes repeatedly over the course of several hours.
You may experience memory loss in the hours before the attack, and you’ll probably have no lasting memory of the experience.
Scientists think that TGA occurs as the result of seizure-like activity or a brief blockage of the blood vessels supplying your brain. It occurs more frequently in middle-aged and older adults.
Infantile or childhood amnesia
Most people can’t remember the first 3 to 5 years of life. This common phenomenon is called infantile or childhood amnesia.
When you have dissociative amnesia, you have difficulty remembering important information about yourself, such as your name, personal history, or family and friends.
Dissociative amnesia may be caused by a traumatic or stressful event, such as being in combat or being the victim of a crime. It usually occurs suddenly and may last for minutes, hours, or days. In rare cases, it may last for months or years.
Post-traumatic amnesia (PTA)
Most people hospitalized for a traumatic brain injury experience post-traumatic amnesia (PTA), according to research.
PTA may occur after a period of unconsciousness. You’re awake, but you may behave and speak in a bizarre manner that’s not like yourself. You may not be able to remember events from minutes or hours ago.
The length of time that PTA lasts may indicate the severity of the brain injury. PTA may last for less than 1 hour for mild trauma or over 24 hours for a severe brain injury, according to Headway, a charity dedicated to survivors of brain injury.
This type of memory loss may occur when you take certain drugs.
The following are some of the drugs that may cause amnesia:
- benzodiazepines such as alprazolam (Xanax) and chlordiazepoxide (Librium)
- sedatives such as zolpidem (Ambien) and zopiclone (Imovane)
- general anesthesia medications such as pentobarbital sodium (Nembutal Sodium) and phenobarbital
- date rape drugs such as flunitrazepam (Rohypnol) and ketamine
Drug-induced amnesia is usually temporary. It’s especially evident in older adults who may be taking various medications.
Amnesia has a variety of causes.
A memory’s location in your brain is thought to depend on its age.
To lose old memories, you must have widespread brain deterioration. This can be caused by Alzheimer’s disease or other forms of dementia.
People with dementia usually lose more recent memories first and keep older memories longer.
Find out more about the symptoms of dementia.
A depletion of oxygen levels can also affect your entire brain and lead to memory loss. This condition is called anoxia. If the anoxia isn’t severe enough to cause brain damage, the memory loss can be temporary.
Damage to the hippocampus
The hippocampus is the part of the brain and limbic system responsible for memory. Its activities include forming memories, organizing memories, and retrieving them when needed.
The cells of the hippocampus are some of your brain’s most energy-hungry and fragile. They’re most easily disrupted by anoxia and other threats such as toxins.
When your hippocampus is impaired, you’ll have difficulty forming new memories. If your hippocampus is damaged in both halves of your brain, you can develop complete anterograde amnesia.
Traumatic head injuries, as well as stroke, tumors, and infections, can also cause damage to your brain. This damage can include permanent memory problems.
Concussions commonly disrupt memories of the hours, days, or weeks before and after you were injured.
Short-term alcohol use can cause blackout. This is a temporary form of anterograde amnesia.
Long-term alcohol use disorder can cause Wernicke-Korsakoff syndrome, a brain disorder that leads to progressive memory loss due to insufficient vitamin B1 (thiamine). If you develop this condition, you’ll have difficulty forming new memories but may not be aware of it.
Trauma or stress
Severe trauma or stress can also cause dissociative amnesia. With this condition, your mind rejects thoughts, feelings, or information that you’re too overwhelmed to handle.
A specific type of dissociative amnesia called dissociative fugue can lead to unexpected traveling or wandering. It can also lead to amnesia around the circumstances of traveling as well as forgetting other details of your life.
Electroconvulsive therapy (ECT)
If you receive electroconvulsive therapy (ECT) for depression or other conditions, you could experience retrograde amnesia of the weeks or months before your treatment.
You could also experience anterograde amnesia, usually resolving
You may be more likely to have amnesia if you’ve experienced any of the following:
- a history of migraine attacks
- cardiovascular disease risk factors such as high blood pressure or high cholesterol
- brain injury or surgery
- emotional stress
People who have even mild amnesia may experience a diminished quality of life. It may be challenging to perform daily work and social activities due to the difficulty of recalling previous memories and creating new ones.
In some cases, lost memories can’t be recovered.
People with severe amnesia may require round-the-clock supervision.
Amnesia can be diagnosed by a doctor or neurologist. They’ll start by asking questions about your memory loss as well as other symptoms you may have.
They may ask a family member or caregiver to help with their evaluation, since you may not be able to remember the answers to their questions.
The doctor may also use cognitive tests to check your memory or order other diagnostic tests.
For example, they may use an MRI or a CT scan to check for signs of brain damage.
They may use blood tests to check for nutritional deficiencies that could affect cognitive function, such as insufficient levels of vitamin B1, vitamin B12 (cobalamin), or vitamin D.
Blood tests can also indicate infections that can cause memory loss, such as Lyme disease, HIV, or syphilis.
If you’re concerned about your memory loss and don’t already have a neurologist, you can view doctors in your area through the Healthline FindCare tool.
To treat amnesia, your doctor will focus on the underlying cause of your condition.
Chemically induced amnesia, from alcohol for example, can be resolved through detoxification. Once the drug is out of your system, your memory problems will probably subside.
Amnesia from mild head trauma may resolve without treatment within minutes or hours. Amnesia from a severe head injury may last up to 1 week. In rare cases, amnesia from a very severe head injury may last for months.
Amnesia from dementia is often incurable. However, your doctor may prescribe medications to support learning and memory, such as donepezil (Aricept), galantamine (Razadyne ER), or rivastigmine (Exelon).
If you have persistent memory loss, your doctor may recommend occupational therapy. This type of therapy can help you learn new information and memory skills for daily living. Your therapist can also teach you how to use memory aids and techniques for organizing information to make it easier to retrieve.
These healthy habits can lower your risk of blackouts, head injuries, dementia, stroke, and other potential causes of memory loss:
- Avoid heavy use of alcohol or drugs.
- Use protective headgear when you’re playing sports that put you at high risk of concussion.
- Wear a seatbelt when traveling by vehicle.
- Immediately treat infections so they don’t spread to your brain.
- If you’re older, have your eyes checked annually and ask your doctors or pharmacists about prescribed medications that may cause dizziness. This can help prevent falls.
- Stay mentally active throughout your life. For instance, take classes, explore new places, read new books, and play mentally challenging games.
- Stay physically active throughout your life.
- Eat a heart-healthy diet, including fruits, vegetables, whole grains, and low-fat proteins. This helps prevent strokes and other cardiovascular problems that may cause amnesia, and also provides nutrients to promote your brain health.
- Stay hydrated. Research shows that even mild dehydration can adversely affect brain functioning, especially in women.
Although amnesia can be permanent in rare cases, it usually resolves on its own. Living with amnesia and performing day-to-day activities may be challenging, and you may need to rely on help from others. A healthy lifestyle may help lower your risk of amnesia.