What Is Synesthesia Disorder? Synesthesia Types And Sensory Overlap

"What color is your seven?" It might seem like a strange question to ask, but if you have synesthesia, you may have an answer. If you or someone you know has a different way of experiencing the world through their senses, you may benefit from learning about what synesthesia is and how to cope with it.

What is synesthesia?

The word synesthesia means “joined sensation” or “together sensation.” It comes from ancient Greek: syn, meaning union, and aesthesis, meaning sensation. It's a neurological condition in which the stimulation of one sense or cognitive area brings about another sensory or cognitive experience, essentially blending two or more of the five main senses.

How synesthesia affects sensory perception

To understand how synesthesia works, it can help to understand how sensory input is processed. There are three steps: 

1. Detection. First, your senses pick up something that is happening around you, whether you see something with your eyes or hear something with your ears. 
2. Signaling. Next, your senses send a signal to your brain, communicating what they are experiencing. For example, your eyes would convey the shapes and colors they’re seeing, and your ears would send signals about hearing sounds.
3. Processing. Finally, the brain receives this sensory information and sends it to a specific area for processing. This step helps you make sense of what you’re experiencing.

In other words, your five senses tell the brain what they are detecting, and your brain takes that information and tries to make sense of it to help you understand the world around you. 

For people with synesthesia, sometimes referred to as having atypical cross-modal experiences, the processing step works a little differently. Rather than the brain sending information from a perceptual experience to one area of the brain, it sends it to two or more at the same time. This means the person experiences a primary effect (such as recognizing that the sound you're hearing is music) and a secondary effect (such as seeing multiple colors associated with the music). As this processing occurs in the brain, these are involuntary experiences; the person has no control over how their brain processes a sensory stimulus or the synesthetic associations it makes.

Is synesthesia a mental health condition?

Synesthesia vs mental illness

Although synesthesia involves unusual sensory experiences, it is not a mental illness, and the experience of synesthesia should not be confused with hallucinations or psychosis. 

In psychotic conditions such as schizophrenia, hallucinations occur unpredictably and without an external cause, and the person experiencing them usually cannot distinguish them from reality. 

Synesthesia is very different. Synesthetic experiences are always triggered by a specific stimulus, are consistent across time, and the synesthete remains fully aware that their perception differs from others around them.

Types of synesthesia

There are two broad types of synesthesia: projective and associative.

• Projective synesthesia involves seeing actual colors, forms, or shapes after sensory or cognitive stimulation.
• Associative synesthesia involves feeling a strong, involuntary connection between sensory and cognitive stimulation on the one hand and colors, forms, or shapes on the other.

In addition to these, there are multiple forms of synesthesia that involve multiple combinations of senses.

• Grapheme-color synesthesia. This is one of the visual forms of synesthesia. People with this type of synesthesia associate colors with letters or numbers (i.e., the number 3 is indigo blue, the number 4 is green). 
• Sound-color synesthesia. In sound-color synesthesia, people associate certain sounds with colors or shapes (i.e., hearing birdsong may coincide with multicolored swirls, and a deep voice may be perceived as dark blue. This form of synesthesia can also occur when people hear music.
• Taste and word-based synesthesia. Some people with synesthesia taste words, names, or sounds. Hearing a word may trigger real sensory taste experiences, like when you eat foods with distinct flavors.
• Spatial sequence and mirror-touch synesthesia. Mirror-touch synesthetes may feel what someone else feels. For example, if they see someone holding their hands near a heater, their hands may feel warm, or if they see someone hit their head, they may feel pain.
• Less common forms of synesthesia: Some of these include number-form synesthesia, wherein a person visualizes a number map image when thinking of a number; ordinal-linguistic personification, in which a person associates numbers, letters, months, and so forth with certain personality traits (i.e., generosity and January, greed and the number ‘7’); and swimming-style synesthesia, where different swimming strokes trigger specific color experiences.

How common is synesthesia, and who experiences it?

Synesthesia is fairly uncommon, and certain types of synesthesia are even rarer. The estimated rate of synesthesia varies depending on language and culture. Studies on synesthesia found the prevalence to be 4.4% of the population.

What causes synesthesia?

No clear, singular cause has yet been discovered that explains why synesthesia happens. It can be induced by using psychedelic drugs. It can happen during the growth and development stages of childhood, and some research suggests it can be induced in non-synesthetes through sensory deprivation. You can acquire it later in life as well. Below, we take a closer look at some of these potential causes.

Brain development and genetic factors

Understanding brain development can help to understand what might be behind the development of synesthesia. 

People with synesthesia are believed to have more connections between the sensory regions of their brains, which allows different senses to interact in ways that they usually don’t. These connections create pathways through which one sensory input can simultaneously trigger the expected response and a response in another sensory area. Synesthesia research suggests that the primary visual cortex may be involved in these cross-sensory responses, with brain imaging studies suggesting that most synesthetes show atypical activation in visual brain regions when processing non-visual information.

The presence of these extra connections suggests that brain development in synesthetes may differ from typical brain development early in life. Where most brains undergo a process of refining and reducing their neural connections over time, synesthetic brains appear to maintain a broader network of cross-sensory links, laying the foundation for the blended perceptual experiences the condition produces.

Much of this developmental difference is thought to be inherited. Developmental synesthesia, which is the variety that is present from birth and persists throughout life, has a recognized genetic component. Developmental synesthetes often have close relatives who are also synesthetes, though they may have different sensory pairings. For example, a parent might experience colors when hearing music, but their child may taste words or see shapes.

Theories behind synesthesia

Key theories as to the cause of synesthesia include:

• Cross-activation theory suggests synesthesia results from heightened connectivity between sensory regions of the brain, causing one sensory area to inadvertently trigger another
• Location of sensory regions may be a key factor, as brain areas processing different senses often sit close together, which makes cross-activation a possible mechanism for these blended sensory experiences.
• Structural brain differences identified in synesthetes, such as more connections between sensory regions, may support the cross-activation model.
• Cognitive and perceptual processes may also be a contributing factor, with researchers arguing that learned associations shape which sensory pairings develop.

What are effective ways to cope with synesthesia?

Many people who have synesthesia believe that it's the most normal and natural thing in the world for them. They may have few or no problems functioning; in fact, they may find that their synesthesia helps them function better and offers sensory enhancements for their experiences.

However, that isn't true for everyone. If you have synesthesia, you may perceive that it's something you have to be ashamed of or hide from others. You may have learned that the way you perceive things is different from others and fear that it is unacceptable.

Another problem some synesthetes report is sensory overload. Because each stimulation elicits multiple sensations, they may have trouble in stimulating environments. In these cases, it can be beneficial to focus on managing overwhelm with various coping skills, as there is currently no way to eliminate developmental synesthesia.

If you do feel overwhelmed by your synesthetic experiences or need help coping with distressing sensory experiences, you can find a way to manage the sensory overload when it happens. Many synesthetes practice meditation or deep breathing exercises to help with sensory regulation. Talking to someone who has experience with synesthesia can be helpful as well, because they may have learned about techniques for moving away from too much outside input.

Do I need therapy for synesthesia?

Technically, synesthesia is not a disorder; it’s simply a different type of sensory perception that impacts your unique experience of the world. As a result, many people who live with synesthesia don’t believe that they need therapy for this condition at all. So, if you have synesthesia and you feel perfectly happy, well-adjusted, and pleased with your synesthetic capabilities, then that’s awesome! If that’s your reality, then there is no reason to get synesthesia treated.

If your experience with synesthesia is a little less positive, that’s okay. If you are feeling emotional or are experiencing different symptoms, like sensory overload or anxiety, getting help from a professional can be beneficial. You don’t have to be happy about synesthesia’s impact on your experience with the world, and it’s okay if you want some extra mental health support.

Talk to a mental health professional 

If you are having problems due to your synesthesia or others' attitudes towards it, you might benefit from talking to a therapist. A therapist can help you work through your feelings and experiences and develop healthy coping mechanisms that will empower you to navigate life in a happier and healthier way. Your therapist can also teach you relaxation techniques and help you build self-esteem. They can offer emotional support and help you connect with others in the synesthetic community.

BetterHelp can empower you to connect with a licensed mental health counselor if you need assistance with this or other mental health questions. You'll be matched with a therapist who can help you in a way that works for you. With the right help, you can learn to see, appreciate, and take full advantage of the unique perspective you have that others can only imagine!

The benefits of online therapy

As discussed above, therapy can help build self-esteem. Low self-esteem can make it difficult to attend in-person sessions. This is where online therapy comes in. In addition, online therapy offers lower pricing than in-person therapy because online therapists don’t have to pay for costs like renting an office. BetterHelp’s licensed therapists have helped people, including those with synesthesia, improve their self-esteem. Read below for some reviews of BetterHelp therapists from people experiencing similar issues.