Have you ever experienced the eerie sensation that you've lived through a particular moment before, even though you're certain it's the first time it's happening? This phenomenon is commonly known as déjà vu, a French term meaning "already seen." Déjà vu generally occurs when we get a strange feeling of familiarity regarding an event or current situation that we couldn't possibly have experienced before. Most people have felt that a new place or situation feels familiar for no reason.  Many people think of deja vu experiences as a sort of "glitch" in our brains, where two thoughts crash into each other, causing an odd feeling of recognition, as though we had encountered that exact situation before. While scientists and psychologists aren't exactly sure what causes déjà vu, it may be linked to how we process memories. Experiencing déjà vu doesn't usually mean there's anything wrong with your mental health, but if any experiences of déjà vu have had lasting effects on your psyche or emotions, it may be helpful to discuss them with a therapist in person or online.

Déjà vu meaning

In general, déjà vu is a phenomenon in which a person suddenly feels a sense of familiarity with a present situation, even though they know they have never encountered it before. It can be unsettling, leaving many people perplexed about how such a feeling is possible. Typically, déjà vu is harmless and occurs infrequently, but in some cases, it could be a symptom of a neurological condition, such as temporal lobe epilepsy.

Possible causes of déjà vu 

Neurological theories

Alternatively, there are neurological theories that tie déjà vu to unusual activity in the brain. The temporal lobes of the brain may be involved in the recall of memories and other familiar situations. Current directions in psychological science research suggest that déjà vu might result from a minor seizure in the temporal lobe (even in people without epilepsy) or a delay in the transmission of information from our senses (like our eyes and ears) to our brain.

While we currently understand so much more about the brain than ever before, the neural pathways of recognition, recollection, and memories are still only vaguely understood by scientists, as are many of the functions of the spinal cord and the central nervous system. Deja vu seems more likely to occur during times of fatigue or sleep deprivation, perhaps because the brain is less able to focus. 

Short-term memory glitches

Psychological science may also provide another alternative explanation, suggesting that déjà vu could be linked to glitches in our short-term memory processing. As a result, we might mistake a second perception of an event as a completely new one. If we see, hear, or feel something twice in a short period of time, our brain might fail to recognize it as the same event. Instead, it may treat the current situation as two separate incidents, causing the sensation of déjà vu.

Deja vu and related phenomena jamais vu and presque vu

Neuroscience and psychology also study jamais vu and presque vu, which are strange feelings related to deja vu experiences, yet are completely different experiences altogether. Jamais vu (French for “never seen”) is an unsettling moment in which a familiar situation suddenly feels strange. Presque vu (French for “almost seen”)  is when we realize we remember something (words, people, places), but then realize we are unsure of what it is we wanted to remember.

Common triggers and contributing factors

Overall health can be a factor in the frequency of deja vu experiences. Some of the most common reasons for increased deja vu include:

• Fatigue or sleep deprivation
• Acute stress or chronic stress
• Physical stress or physical exhaustion
• Some mental health issues like health anxiety 
• Oversensization  

In some cases, when deja vu is happening more often, it can be a sign to examine overall health. 

The effects of déjà vu on daily life 

Experiencing déjà vu may make us more aware of our mental state and cognitive processes, but how does it affect us day to day? Whether you experience déjà vu occasionally or frequently, you might find that it changes how you see the world, make decisions, and interact with other people. 

• Altering perception of reality: Déjà vu can sometimes change our perception of reality, which can create a surreal feeling. It can make us question how we remember certain events and how we experience time and our past. Even though it can be a bit confusing, it can also present an opportunity to think more deeply about how our mind works and who we are as people, which may help us learn more about ourselves.
• Influence on decision-making: Déjà vu may also influence our decision-making processes. When we're in the middle of a déjà vu moment, we might feel a strong urge to do or not do something because it feels “right.” This feeling of knowing something, even if it's not accurate, may affect our judgment in unexpected ways, potentially pushing us to make decisions that we might not have made otherwise.

These are just a couple of ways that déjà vu can affect our lives. Occasional déjà vu is not known to have a negative effect on daily life. However, if you experience it often, you may be living with a more serious underlying concern.  

Types of déjà vu  

There can be several different types of déjà vu, each of which may assist in our understanding of why this phenomenon occurs. Let's explore three main types: associative déjà vu, biological déjà vu, and chronostasis.

Associative déjà vu

Associative déjà vu generally occurs when something happening now reminds you of something similar that happened before. Your brain may link the current event to a past one because they have some things in common. This type of déjà vu is generally harmless and affects a wide range of people.

Biological déjà vu

Biological déjà vu usually involves the brain's inner workings, specifically the memory processing centers. This type of déjà vu is usually tied to temporal lobe epilepsy and happens when there is a small glitch or delay in the brain's processing of sensory input. The brain may momentarily perceive the information twice, leading to the experience of déjà vu. 

Chronostasis

Chronostasis, also called the "stopped clock" phenomenon, can be similar to déjà vu, in which it seems like time is paused. This experience can be caused by rapid eye movement, causing the person to feel like they have seen the same moment twice. It can also happen if your attention drifts for a second or if you shift your gaze suddenly.

Other types of déjà vu and similar phenomena 

Beyond these three main types of déjà vu, some other forms of this phenomenon could include the following: 

• Dream-induced déjà vu: Dream-induced déjà vu may occur when a current event or situation feels like a replay of a dream you’ve had in the past. These experiences can feel vivid, almost as if you’re living out a scene that was dreamt up days, weeks, or even months ago. These episodes might seem puzzling, but they may have to do with how our brain processes memories when we're sleeping. Certain things we've seen, heard, or done during the day might get mixed into our dreams, and coming across the same things when we're awake might cause us to feel a sense of déjà vu.
• Premonition-based déjà vu: Premonition-based déjà vu can be described as the sensation of having “foreseen” a current event or situation. During these experiences, it can seem like you instinctively know what's about to occur next, which can make you feel like you're reliving the moment. While this may sound supernatural, some theories suggest it could be linked to our subconscious mind. This part of our mind might notice patterns or signs that our conscious mind overlooks. When the event we unknowingly predicted does happen, we may experience a sense of déjà vu because it feels like we've seen it before.
• Déjà vu vs. deja vécu: One particular variant of déjà vu may be déjà vécu, which can be translated from French as "I have already experienced this." While some people may confuse déjà vécu with déjà vu, the experiences tend to be different. Déjà vécu usually involves a much more detailed sense of reliving an event, such as noticing particular smells and sounds or predicting what will come next. This phenomenon is often more intense than the familiarity experienced during typical déjà vu.

Recognizing the different types of déjà vu may provide insight into how our brains work and how we process memories. Even though they can feel a bit strange, most types of déjà vu are harmless and not a cause for concern.

Is Déjà vu a problem?

Nearly 97% of people have experienced déjà vu at least once in their lives. For many, this sensation can come up regularly. Even though it's usually nothing to worry about, there are times when it might point toward a potential problem with brain function. This can be especially true for individuals with underlying neurological conditions.

Clinical neuroscience has found some connections between frequent deja vu and temporal lobe epilepsy; they may be an aspect of temporal lobe seizures. Certain medications can make deja vu more prevalent, as can autoimmune diseases, and in rare cases chronic inflammation. If you notice that you are experiencing deja vu more than is usual for you, it can be a good idea to get a medical evaluation of your overall health, simply to rule out any medical reason. 

When to seek help for déjà vu 

Someone who often experiences feelings of déjà vu, along with other symptoms, such as confusion, anxiety, or memory problems, may have a certain medical condition, such as epilepsy or temporal lobe dysfunction. 

In these cases, it can be important to visit a healthcare provider who can evaluate whether there’s a cause for concern and recommend various tests or treatments. If you experience déjà vu frequently, you may want to keep an eye on your mental health and be aware of any changes in how often or how strongly you experience episodes of déjà vu.

In some cases, mental health can impact deja vu, and vice versa. Psychology research shows that emotional experiences, health anxiety, and other factors can cause stress, and in turn stress impacts the body, and can create a wide range of physical and emotional symptoms like fatigue, lack of motivation, and unregulated emotions. Deja vu can be a sign that it’s time to seek support from a mental health professional. 

Coping strategies: staying calm during a deja vu experience

Deja vu can be a strange feeling, and for some may cause distress. In the moment it is happening, reality can feel skewed. If you find yourself feeling stressed after deja vu, take a moment to focus and bring your awareness back to the present moment. Grounding techniques such as breathing exercises or progressive muscle relaxation can help. If possible, you may reach out to talk to a friend or family member as a distraction.    

Therapy can help you process instances of déjà vu 

If you’re experiencing repeated instances of déjà vu, or if you’ve had a particularly intense case of déjà vu, you may experience certain effects on your mental health. Whether you’re feeling stressed or are simply curious about insights you’ve gained, speaking with a therapist may be beneficial.

Benefits of online therapy

It can be difficult to find the time for therapy in today’s busy world, but online platforms like BetterHelp may offer a more accessible option for getting the support you deserve. Once you sign up on BetterHelp, you’ll usually be matched with a licensed therapist within 48 hours. From there, you can decide whether they’re the right fit for you or choose to switch providers until you find one who meets your needs. Through video chats, phone calls, or in-app messaging, you can connect with your therapist at anytime from anywhere.  

Effectiveness of online therapy

While more research may be needed regarding the efficacy of online therapy for déjà vu, evidence suggests that online therapy can be an effective treatment for a variety of mental health disorders. A 2022 meta-analysis evaluated the efficacy of online therapy in comparison to traditional in-office treatment. It found that both modes of therapy generally produced the same client outcomes.