What Is Synesthesia, And Can It Affect Mental Health?

Medically reviewed by Julie Dodson, MA, LCSW
Updated June 27, 2024by BetterHelp Editorial Team

You may have heard the term “synesthesia” used to describe the phenomenon of experiencing one sense at the same time as another—for example, the ability to “hear shapes” or “taste words.” While synesthesia isn’t usually categorized as a mental illness, it can still be an isolating experience for those who live with it. Online therapy can be a valuable form of support, and self-care and connecting with a community of other synesthetes may also be helpful.

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Synesthesia doesn’t have to be isolating

What is synesthesia?

The American Psychological Association defines synesthesia as “a condition in which stimulation of one sense generates a simultaneous sensation in another.” 

In other words, those with synesthesia (sometimes called synesthetes) may experience a sensation generally associated with a sense other than the one that’s being stimulated. For example, a person with synesthesia might perceive certain sounds as having specific smells or experience various tastes in response to seeing different shapes.

In general, a key component of synesthesia is consistency. This means that synesthetes normally experience the same sensory connections each time a certain sense is stimulated. For example, the same sound might be associated with the same color in a variety of settings and contexts. 

While a variety of metrics and standards have been proposed by researchers, there is currently no standard “synesthesia test” used to diagnose the condition. 

What are the types of synesthesia?

Synesthesia may take a wide variety of forms, and different people tend to experience it in different ways. Forms of synesthesia may include:

Grapheme-color synesthesia

This form of synesthesia generally involves a person perceiving certain colors when they look at certain letters, numbers, or words. 

Sound-to-color synesthesia

This form of synesthesia usually involves being able to “see” sounds as different colors. Some synesthetes report that they perceive these synesthetic colors in their minds, while others may actually see them. 

Lexical-gustatory synesthesia

Individuals with this form of synesthesia may perceive different tastes when they hear or read words. 

Mirror-touch synesthesia

Those with mirror-touch synesthesia may experience tactile sensations when they witness someone else experiencing those same sensations. For example, someone with mirror-touch synesthesia might feel the sensation of their hand being touched when they see someone else having their hand touched. 

These are just a few examples of the many forms synesthesia can take. A range of other variations may be possible as well. 

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What are the causes of synesthesia?

Various research has been conducted on the cognitive neuroscience behind synesthesia. Thus, several different theories have been proposed for the mechanisms involved. Some researchers theorize that those with synesthesia have increased communication between the different subsections of their brains (e.g., the areas of the visual cortex responsible for processing color and motion). 

Those with synesthesia are typically either born with it or develop it early in childhood, although it may be possible to develop synesthesia later in life (for instance, after a brain injury). The field of human neuroscience is constantly evolving, and research is ongoing. Still, current research suggests that there may be a genetic component involved in the development of synesthesia. 

In some cases, synesthesia may also be temporarily induced by substances like hallucinogens, cannabis, and caffeine.

Can synesthesia affect your mental health?

It is generally recognized that synesthesia is not a harmful condition, and it is not considered a disorder or mental illness. Some individuals with synesthesia may even enjoy the ways it affects their perception. That said, synesthesia is still a relatively rare condition. Although updated research may be necessary, existing studies suggest that synesthesia may be present among 2% to 4% of the population.

For this reason, those with synesthesia may find themselves experiencing feelings of isolation or stigma for what others may consider to be unusual perceptions. This may lead to feelings of shame, loneliness, or an urge to hide their condition from others. In other cases, those with synesthesia may experience unpleasant sensations that may be distressing (for example, experiencing others’ pain among those with mirror-touch synesthesia). 

A variety of strategies can help those with synesthesia connect with others, tend to their mental health, and support their overall well-being, including the following:

  • Practicing self-care strategies, such as relaxation, regular exercise, and recreation
  • Connecting with other people who have synesthesia to socialize, share experiences, and get support
  • Practicing mindfulness, deep breathing, and other relaxation strategies to manage unpleasant sensations

For those in search of additional support, therapy may also be a valuable resource. With the help of a licensed therapist, those with synesthesia can discuss their experiences and perceptions in a safe, non-judgmental environment. Therapy may also help them address challenges as they arise and develop strategies to support their mental health and overall quality of life. 

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Synesthesia doesn’t have to be isolating

Benefits of online therapy

Attending traditional therapy may not always be practical, particularly for those with full schedules or conflicting commitments. Additionally, those living with synesthesia may find that they need more support and guidance in their daily lives than they can get in a single weekly therapy session. In these cases, online therapy through a platform like BetterHelp may be a helpful alternative. With this form of remote therapy, you can attend sessions from wherever is most convenient and send messages to your therapist outside of scheduled therapy sessions; they will typically try to respond when they are able.

Effectiveness of online therapy

Online therapy can be an effective and cost-efficient alternative to traditional therapy. Although more research may be needed regarding the efficacy of online therapy as a form of support for those with synesthesia, one study found that online cognitive behavioral therapy (CBT) could be an effective treatment option for those living with depression, generalized anxiety disorder, panic disorder, adjustment disorder, bipolar disorder, and phobias. 

Takeaway

Synesthesia is a condition affecting an estimated 2% to 4% of the population in which an individual experiences an unrelated, simultaneous sensation in response to a sensory stimulus. For example, a person with synesthesia may be able to hear colors or smell sounds. Different forms of synesthesia have been identified, including grapheme-color synesthesia, mirror-touch synesthesia, sound-to-color synesthesia, and lexical gustatory-synesthesia. The causes of synesthesia may be genetic, though research is ongoing. Synesthesia is not typically considered a mental health condition or mental illness, but those who have it may experience feelings of isolation or loneliness due to its rarity. In these cases, strategies such as self-care, mindfulness, relaxation, and connecting with other synesthetes may all be helpful for supporting one’s mental health and well-being. For those in need of more support, therapy—either in-person or online—may also be a valuable resource.
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