7 Common Causes of Forgetfulness

Forgetfulness Unveiled: Identifying Common Causes

Forgetfulness is a common issue that individuals may experience. It can range from forgetting simple everyday tasks such as where the keys were left, to more serious issues such as forgetting important appointments or even medical conditions. While forgetfulness may be a common issue, it is important to identify the root causes of this problem in order to address it effectively.

Identifying the causes of forgetfulness is important because it can help individuals understand whether this is a normal part of aging or if there are other underlying medical or lifestyle-related issues that need attention. In this article, we will delve into the seven most common causes of forgetfulness and provide insights on how to address these issues.

We will start with medical causes, which can include thyroid disorders, vitamin deficiencies, and neurological conditions. Following this, we will discuss lifestyle factors such as lack of sleep, stress, and sedentary habits. Next, we will discuss medication side effects, including antidepressants, benzodiazepines, and statins. Substance abuse, including alcohol, illegal drugs, and prescription drug abuse, will be discussed in the subsequent section.

Psychological factors, including depression, anxiety, and trauma, are also common causes of forgetfulness. Finally, we will touch on aging-related forgetfulness and early signs of dementia.

By the end of this article, individuals experiencing forgetfulness will be equipped with knowledge on how to address the issue and understanding the importance of seeking medical advice if necessary. Remember, identifying the root cause is the first step towards effectively addressing forgetfulness, which can ultimately help individuals maintain their quality of life.

Medical Causes of Forgetfulness

Forgetfulness can have various medical causes. Here are some of the most common ones:

Thyroid disorders

An underactive thyroid gland, also known as hypothyroidism, can cause forgetfulness. The thyroid gland produces hormones that regulate metabolism and energy levels. When the gland does not produce enough hormones, individuals may experience symptoms such as fatigue, weight gain, and forgetfulness. Treatment of hypothyroidism generally involves taking thyroid hormone medication.

Vitamin deficiencies

Deficiencies in certain vitamins and minerals can contribute to forgetfulness. For example, a lack of vitamin B12 can cause memory problems, confusion, and fatigue. Vitamin B12 is found in animal products, such as meat, fish, and dairy. Individuals who follow a vegan or vegetarian diet may be at risk of developing a B12 deficiency. Other vitamins and minerals that are important for brain health and memory include vitamin D, magnesium, and omega-3 fatty acids.

Neurological conditions

Certain neurological conditions, such as Alzheimer's disease, can cause forgetfulness. Alzheimer's disease is a progressive brain disorder that affects memory, thinking, and behavior. Other neurological conditions, such as multiple sclerosis, Parkinson's disease, and brain tumors, can also cause memory problems. Treatment for these conditions is focused on managing symptoms and slowing their progression.

In summary, forgetfulness can have various medical causes, including thyroid disorders, vitamin deficiencies, and neurological conditions. It's important to seek medical attention if you are experiencing memory problems to determine the underlying cause and receive appropriate treatment.

Lifestyle Factors and Forgetfulness

Apart from medical conditions, certain lifestyle factors can also contribute to forgetfulness. Here are some of the most common:

Lack of Sleep:

Getting adequate sleep is vital for memory consolidation, and a lack of sleep can have negative effects on learning, cognition, and memory. Sleep deprivation can cause forgetfulness, attention deficits, and difficulty concentrating. Research has also linked sleep apnea to poor memory function and thinking abilities.


Stressful life events, which can include financial problems, relationship issues, or work-related stress, can cause forgetfulness. When stressed, the body releases hormones, such as cortisol, that can interfere with the brain's memory-forming process. Chronic stress has also been linked to an increased risk of developing Alzheimer's disease.

Sedentary Lifestyle:

Engaging in regular physical activity not only benefits the body but also helps to maintain cognitive abilities, including memory. Conversely, a sedentary lifestyle can negatively affect brain health. Research has shown that a lack of physical activity is linked to an increased risk of developing cognitive impairment and dementia.

In summary, lifestyle factors, such as lack of sleep, stress, and a sedentary lifestyle, can contribute to forgetfulness. However, making small changes to improve sleep, reduce stress, and increase physical activity can help to improve memory and overall brain health.

Medication Side Effects and Forgetfulness

Medications can also be a culprit for forgetfulness. Several types of medications have been linked to cognitive impairment and memory problems. Here are some of the most common:


Antidepressant medications that belong to the class of selective serotonin reuptake inhibitors (SSRIs) are widely prescribed to treat depression and anxiety. However, studies have shown that long-term use of SSRIs can cause memory problems and cognitive decline, particularly in older adults. The exact mechanism behind this association is still unknown.


Benzodiazepines are medications used to treat anxiety, insomnia, and seizures. These medications enhance the effects of gamma-aminobutyric acid (GABA), a neurotransmitter that slows down activity in the brain. However, long-term use of benzodiazepines has been linked to memory problems, cognitive decline, and even an increased risk of developing Alzheimer's disease.


Statins are medications used to lower cholesterol levels and reduce the risk of developing heart disease. However, studies have shown that statins can also cause memory problems, particularly in individuals who are already at risk of cognitive impairment. The exact mechanism behind this association is still unclear, but it is believed that statins may interfere with the production of cholesterol, a crucial component for brain function.

It is important to note that not every individual who takes these medications will experience memory problems. However, if you are taking any of these medications and notice any changes in your memory or cognitive abilities, it is important to speak with your healthcare provider. They may be able to adjust your medication or offer alternative treatments that do not cause cognitive impairment.

Substance Abuse and Forgetfulness

Substance abuse, whether it be alcohol, illegal drugs or prescription drug abuse, can also cause forgetfulness. Here are some ways substance abuse can impact memory and cognitive abilities:


Alcohol is a central nervous system depressant that slows down brain activity. Long-term excessive alcohol consumption can lead to memory problems and cognitive impairment, particularly in the areas of attention, learning, and memory retrieval. This is due to the damage alcohol causes to the hippocampus, a brain structure crucial for memory consolidation.

Illegal drugs:

Illegal drugs, such as cocaine and methamphetamine, can also cause memory problems. These drugs affect the natural rhythm of the brain, which can lead to cognitive impairment and memory deficits. Long-term use of these drugs can also cause permanent damage to the brain, leading to irreversible memory problems and cognitive decline.

Prescription drug abuse:

Prescription drug abuse, particularly of medications that affect the central nervous system, can also lead to memory problems and cognitive decline. Drugs like opioids, benzodiazepines, and other sedatives can cause memory problems, confusion, and cognitive impairment. Furthermore, the misuse of prescription drugs can often lead to addiction, which can also exacerbate memory problems and cognitive impairment.

It is important to recognize the impact of substance abuse on cognitive abilities and memory, and seek help if needed. Treatment and recovery from substance abuse can lead to improvements in memory and cognitive function, but it is important to seek professional help and support.

Psychological Factors and Forgetfulness

Psychological factors, particularly conditions such as depression, anxiety, and trauma, can all contribute to forgetfulness. Here is a closer look at each of these factors and how they can affect memory and cognitive abilities:


Depression is a mood disorder that can affect a person's ability to concentrate, make decisions, and remember things. It can cause forgetfulness, memory problems, and cognitive impairment, particularly in the areas of attention and working memory. These memory problems can be exacerbated by feelings of hopelessness and loss of interest in hobbies or activities that provide mental stimulation.


Anxiety is another common psychological factor that can contribute to forgetfulness. Chronic anxiety can lead to elevated cortisol levels, which can damage the hippocampus and other areas of the brain responsible for memory consolidation. This can cause memory problems, particularly in the areas of attention, concentration, and short-term memory.


Trauma can also play a role in forgetfulness and memory impairment. Traumatic experiences, such as physical or emotional abuse, can lead to post-traumatic stress disorder (PTSD). Those with PTSD may have difficulty concentrating, disassociating, and experience panic attacks and nightmares. Consequently, they may struggle with memory problems, attention, and concentration.

It is essential to recognize the role of psychological factors in forgetfulness. Treating psychological conditions can help alleviate memory problems and cognitive impairment. People with depression or anxiety may benefit from talk therapy, medication, or a combination of the two. Those with trauma need specific and effective treatment.

Aging and Dementia

As we age, forgetfulness can become more common. Here is a closer look at the natural aging process and the progression of cognitive decline:

Normal age-related forgetfulness:

It is normal for people to experience some degree of forgetfulness as they age. For example, sometimes an individual may forget where they placed their keys or have difficulty finding the right words. These are normal age-related changes that do not usually cause problems with daily activities.

Mild Cognitive Impairment:

However, when forgetfulness begins to interfere with daily life and activities, it may be a sign of mild cognitive impairment (MCI). Those experiencing MCI may struggle to recall details or names of familiar persons. They may also forget things they just read or lose track of their daily tasks. It is important to note that not everyone with MCI will develop dementia, virus some individuals will.

Early Signs of Dementia:

While forgetfulness is a normal part of aging, persistent memory problems that become more severe may be signs of early-stage dementia. Often, the earliest signs of dementia are struggle with spatial navigation, short-term memory, language, and problem-solving abilities. Individuals may get lost in familiar places and forget the names of familiar people or objects. They may also experience confusion and difficulty with understanding and following instructions, both verbal and written.

In conclusion, while forgetfulness is a normal part of the aging process, it is important to be aware of the early signs of cognitive decline and seek medical attention if necessary. Early detection and management can significantly improve the quality of life and cognitive functioning for those experiencing memory problems.


Forgetfulness is a common problem that can significantly impact daily life. While forgetfulness is often a natural part of the aging process, there may be an underlying medical condition that is causing memory problems. Identifying the cause of forgetfulness is key to preventing further memory loss or cognitive decline.

Here are the main points to take away from this article:

- Forgetfulness can be caused by a variety of medical, lifestyle, and psychological factors.
- Common medical causes of forgetfulness include thyroid disorders, vitamin deficiencies, and neurological conditions.
- Lifestyle factors such as lack of sleep, stress, and a sedentary lifestyle can also contribute to forgetfulness.
- Medications, substance abuse, and psychological factors such as depression and anxiety can also cause memory problems.
- Normal age-related forgetfulness is common, but persistent memory problems may be a sign of mild cognitive impairment or early-stage dementia.
- It is important to seek medical attention if forgetfulness is interfering with daily life and activities.
- Tips for reducing forgetfulness include getting enough sleep, staying mentally and physically active, and eating a healthy diet.

In Summary, identifying the underlying cause of forgetfulness is crucial in order to prevent further memory loss and cognitive decline. If you or someone you know is experiencing memory problems that interfere with daily life and activities, it is important to seek medical attention. By adopting healthy lifestyle habits and remembering to practice self-care, it is possible to reduce forgetfulness and preserve cognitive function throughout life.

William H. McDaniel, MD

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School.

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