Long-term memory consists of memories that the brain has stored over an extended period of time. These memories can be from an hour ago or from decades earlier.

People with long-term memory loss have difficulty remembering important facts, events, people, or skills.

Although aging can affect long-term memory, numerous health conditions can also cause a person to experience memory loss.

Keep reading to learn more about what long-term memory is, some conditions that may cause long-term memory loss, and some ways that people can improve their long-term memory.

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Long-term memory refers to the memory process in the brain that takes information from the short-term memory store and creates long lasting memories. These memories can be from an hour ago or several decades ago.

Long-term memory can hold an unlimited amount of information for an indefinite period of time. Short-term memories become long-term memories in a region of the brain called the hippocampus. Another part of the brain called the cortex stores these long-term memories.

There are two types of long-term memory: procedural and declarative.

Procedural long-term memories are information related to activities learned through practice and repetition, such as driving a car.

Declarative long-term memories are information about facts, rules, events, definitions, and experiences that someone can recall when necessary.

Learn more about types of memory here.

Long-term memory loss occurs when someone starts forgetting or being unable to recall things that they should know or things that they knew previously.

Some common symptoms of long-term memory loss include:

  • forgetting important dates, rules, or facts
  • forgetting how to do important activities, such as how to drive, ride a bike, or use a computer
  • forgetting people’s names, what they look like, or who they are
  • forgetting the names of common objects or substituting the wrong words, such as calling a cell phone a book or a table a chair
  • filling in gaps in memory with false information
  • getting lost in places that one is familiar with

Many people become a little more forgetful as they age, and this can be a normal part of aging.

However, if forgetfulness becomes frequent or impacts a person’s ability to function in their daily life, they may wish to contact a doctor to see if they have an underlying medical condition.

Some of the more common causes of long-term memory loss include the following.

Aging

As the brain ages, changes may take place that make it harder for a person to learn new information or skills or recall memories. That said, aging alone does not normally cause serious long-term memory problems.

Neurodegenerative conditions

Neurodegenerative conditions cause the gradual death of nerve cells in the brain. This process often leads to memory loss and other brain changes. One example of a neurodegenerative condition is dementia.

Dementia causes irreversible changes to a person’s learning, reasoning, and thinking abilities, and it causes both short-term and long-term memory loss.

The most common form of dementia is Alzheimer’s disease, though dementia is also a symptom of several neurological conditions, including:

Long-term memory loss tends to occur during the later stages of dementia and other neurodegenerative conditions.

Brain infections

Infections that affect the brain — such as meningitis, encephalitis, and HIVcan cause damage to the brain that leads to memory loss.

Memory loss related to brain infections may resolve with appropriate treatment.

Depending on how severe or widespread the damage is, or where it occurs, a person may require medications, supportive care, or long-term therapy to try to recover their memory or manage any memory loss that the infection has caused.

Brain tumors

More than 90% of people with brain tumors experience cognitive problems, such as issues with memory, attention, and executive functioning. In some cases, memory loss may resolve or improve with surgery, chemotherapy, or radiation therapy.

Learn more about brain tumors here.

Blood clots, brain hemorrhages, and stroke

Anything that restricts or stops the flow of oxygen-rich blood to the brain can damage or destroy brain cells, which can affect memory, depending on the region of the brain involved.

Whether or not memory loss resolves with treatment — such as surgery or medications — depends on the extent, severity, and location of the brain damage.

Learn more about brain hemorrhages here.

Chronic alcohol misuse

If someone consumes a lot of alcohol over a long period of time, it can cause irreversible damage to parts of the brain involved with long-term memory, such as the hippocampus and cortex.

Learn more about alcohol-related brain damage here.

Head injuries

Any type of head injury that interferes with blood flow to regions of the brain or damages parts of the brain that process long-term memory, such as the hippocampus and cortex, can cause memory problems.

Depending on the severity, location, and extent of the damage, memory loss may or may not resolve with treatment or rehabilitative therapy.

Certain medications

Many medications that can be sedating or cause drowsiness can also interfere with memory. Some medications associated with long-term memory problems include:

  • benzodiazepines, which dampen activity in areas of the brain involved in transferring information from short-term to long-term memory
  • antidepressant medications, which block the activity of key chemical messengers in the brain called serotonin and norepinephrine
  • antiseizure medications, which dampen the activity of the central nervous system (CNS)
  • narcotic medications, which block the activity of signals in the CNS
  • medications for high blood pressure, which block the activity of chemical messengers in the brain, such as norepinephrine and epinephrine
  • Parkinson’s disease medications, which activate pathways in the brain for the chemical messenger dopamine
  • sleeping medications, which have similar actions and effects to benzodiazepines
  • antihistamines, which block the activity of a chemical brain messenger called acetylcholine
  • incontinence medications, which also block the activity of acetylcholine

Certain nutritional deficiencies

Deficiencies of important nutrients that help the brain function properly — including folic acid, thiamine, and vitamin B12 — can cause memory loss.

Chronic thiamine deficiencies can occur due to long-term alcohol misuse.

Hydrocephalus

Hydrocephalus occurs when cerebrospinal fluid builds up in the ventricles of the brain. Cerebrospinal fluid surrounds the brain and spinal cord and protects them from injury. It also helps deliver nutrients to the brain and remove waste.

As brain ventricles enlarge with excess cerebrospinal fluid, they can damage or interfere with surrounding brain tissue, which may cause memory problems.

Learn more about hydrocephalus here.

Thyroid conditions

Thyroid conditions can cause cognitive changes, such as memory loss.

In the case of hypothyroidism, wherein the thyroid glands do not produce enough thyroid hormones, the condition may cause a reduction in the size of the hippocampus, which is an important brain region involved in memory.

Recreational drug use

Many recreational drugs can temporarily interrupt short-term memory and interfere with the formation of new long-term memories. Excessive or severe drug use can also cause damage to the brain that, in turn, leads to long-term memory loss.

Arthritis

Some chronic conditions, such as certain types of arthritis, can cause brain fog, which involves having difficulty remembering new information and recalling older information.

Other causes

Some other, less common causes of long-term memory loss include:

In some cases, psychological conditions can cause someone’s brain functioning or chemistry to change, which can impair long-term memory creation, storage, and retrieval.

Some common psychological or mental health conditions associated with long-term memory loss include:

The treatment options for long-term memory loss depend on the cause.

In some cases, treatment may improve, or even resolve, memory loss. However, conditions that cause brain damage may result in irreversible changes to the brain and permanent, untreatable memory loss.

Some common treatments and remedies for conditions that cause memory loss include:

  • taking antibiotic or antiviral medications for infections
  • undergoing surgery, chemotherapy, or radiation therapy for brain tumors
  • taking vitamin supplements or making dietary changes for vitamin deficiencies
  • taking thyroid hormone medications for thyroid conditions
  • trying stress reduction techniques, such as meditation, yoga, controlled breathing, or exercise
  • trying antidepressants and therapy, such as cognitive behavioral therapy, for depression
  • taking antianxiety medications or trying stress reduction techniques for anxiety
  • getting more sleep for sleep deprivation
  • stopping, tapering, or switching medications that cause memory loss, but only under a doctor’s supervision
  • seeking surgery, medications, rehabilitative therapy, or supportive care for brain bleeds, blood clots, stroke, and heart attack
  • reducing or stopping alcohol consumption, recreational drug use, or cigarette smoking, which may require counseling or therapy
  • undergoing surgery to remove excess cerebrospinal fluid for hydrocephalus
  • taking corticosteroids and immune-suppressing medications for cerebral vasculitis
  • taking pain medications and getting enough sleep and exercise for chronic pain conditions

There are no treatments that can reverse or cure neurodegenerative conditions, though some medications may help slow the progression of mild-to-moderate Alzheimer’s disease. Some medications may also help manage the symptoms of other neurodegenerative conditions.

The National Institute on Aging (NIA) has several tips for managing or improving forgetfulness, including:

  • following a daily routine
  • planning tasks in advance
  • making to-do lists or leaving notes on important devices — such as a coffee maker, computer, or television remote — that explain how and when to use them
  • keeping phone alarms or alerts
  • continually learning new skills and doing tasks that are familiar
  • staying involved and closely connected to a support system, such as family or friends
  • volunteering or becoming more engaged with one’s community or with faith groups
  • putting important items — such as phones, wallets, purses, TV remotes, and glasses — in the same place each day
  • getting proper sleep and exercise
  • eating a healthy, balanced diet
  • controlling or preventing high blood pressure
  • not drinking alcohol or using recreational drugs
  • seeking treatment for depression, severe stress, anxiety, or PTSD
  • doing activities that engage the brain, such as crossword puzzles, Sudoku, and reading

The manufacturers of plenty of supplements, over-the-counter medications, and puzzles claim that their products can reverse memory loss or improve memory.

However, the NIA warns against unproven treatments for memory loss, claiming that none have enough research to support their use. Some may even cause unintended side effects or interfere with other medications that a person is taking.

Learn more tips for improving memory here.

People who think that they are experiencing memory problems should seek the advice of a doctor. They can assess whether the symptoms are a normal part of aging or the cause of an underlying health condition that may require treatment.

People who think that someone close to them may be experiencing memory loss should also encourage them to or help them seek medical attention.

If someone is having problems with their memory, they should check in with a doctor every 6–12 months to see if their condition is improving, worsening, or staying consistent.

Long-term memory refers to the memory process in the brain that takes information from the short-term memory store and creates long lasting memories.

Long-term memory loss can be associated with mid-to-late stage neurodegenerative conditions, such as Alzheimer’s disease, and several other conditions that affect how the brain functions or its chemistry.

A person should contact a doctor about memory problems if they become concerning, as many are improvable or reversible with appropriate treatment and monitoring — as long as permanent brain damage is not the cause.