We each express our emotions differently. But if you feel you don’t have much of an emotional response to life events, here’s what it could mean.

Some people smile or laugh out loud when feeling happy. Others may feel that same sense of joy yet maintain a neutral facial expression.

If you can relate to the latter, this may just be your personality. But it’s also possible that you’re living with something called “flat affect.”

Whether this symptom came on suddenly or you’ve been experiencing it for as long as you can remember, there are many possible causes.

The term “affect” refers to your ability to express emotions. For example, how your face shows happiness, sadness, fear, or anger. It’s also an umbrella term for everything related to your emotions, from your mood to the physical sensations related to them.

Beyond your facial expression, your affect also includes your hand gestures, body language, and even your tone of voice.

A flat affect, then, refers to low or lack of an emotional expression when the situation may merit a more evident reaction. For example, smiling or laughing at a good joke.

A flat affect isn’t a condition on its own. It can be a symptom of a mental health condition, although this isn’t always the case.

While researchers don’t know the exact cause of a flat affect, it may be related to brain chemistry.

More specifically, certain parts of your brain, like the sensorimotor system or the amygdala, may be underactive compared with people who don’t have a flat affect.

While a flat affect is most commonly associated with symptoms of schizophrenia, this isn’t the only explanation for it. Here are some other potential causes.

Antidepressant medications

Certain medications, like antidepressants, can cause a flat affect.

In a 2017 study that examined 3,243 user reviews of antidepressants from three health websites, 41% of reviews reported negative emotional and behavioral effects, including a flat affect.

In this case, the reviewers were taking either:

  • escitalopram (Lexapro)
  • duloxetine (Cymbalta)
  • vilazodone (Viibryd)
  • vortioxetine (Trintellix)

Autism spectrum disorder

Research shows an overlap in symptoms between schizophrenia and autism. This may sometimes include a flat affect, which has confused experts for decades because the two conditions are very different.

Some autistic people may have a hard time expressing emotions or responding to social interactions, which can present as a flat affect.

For example, in a small 2019 study, researchers found that autistic people had more muted muscle movements in their faces when watching films designed to stimulate emotions than a control group.

Dementia

Some forms of dementia can cause changes to the frontal and temporal lobes of the brain, which can sometimes manifest behaviorally as a flat affect.

Although not always the rule, symptoms of dementia may include progressive aphasia (the inability to communicate) and a loss of facial expression, according to the National Institute on Aging.

Depression

As you may know, depression exists on a spectrum.

In some cases, a flat affect may be present along with related symptoms, like anhedonia, or the inability to feel pleasure. This isn’t always the case, though.

Flat affect can result from a decreased emotional response to events around you.

Muscle disorders

Facial paralysis, such as after a stroke or from other muscle disorders, can give someone the appearance of a flat affect.

Parkinson’s disease

According to a small 2021 study, people with Parkinson’s disease may experience hypomimia, more commonly known as a “masked face.” This refers to a progressive decline in facial expression, which can manifest as a flat affect.

Schizophrenia

A flat affect is considered a “negative” symptom of schizophrenia, which means there’s an absence of a certain emotion or behavior.

Research suggests that people living with schizophrenia have a decreased ability to express their emotions, as well as a decreased ability to pick up on the emotional reactions of others.

Schizoid personality disorder

People who live with schizoid personality disorder may sometimes have some symptoms that overlap with schizophrenia.

According to the diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), this includes avoiding social interactions and displaying emotional coldness, detachment, or a flat affect toward others.

Traumatic brain injury

Research shows that 62% of people with traumatic brain injuries experience behavior changes. For some people, this could mean rapidly shifting emotional expressions. For others, it could mean a flat affect.

Having a flat affect doesn’t mean that you don’t feel emotions. Rather, it means that your reactions on the outside don’t necessarily match what you’re feeling on the inside.

For example, let’s say your friends throw you a surprise party. As you walk in the door and everyone shouts “Surprise!” you may feel shocked and excited. But your facial expression may register as apathetic or even bored.

Some telltale signs of a flat affect include:

  • appearing to lack interest
  • avoiding eye contact
  • apathetic body language or nonverbal cues
  • neutral facial expressions
  • monotone or flat voice
  • lack of hand gestures

While a flat affect and emotional blunting may sound like the same thing, they are indeed different (but still related).

Like a flat affect, emotional blunting is a symptom of a condition. It’s a diminished emotional response, like suddenly not laughing at a movie you once found funny.

If you’re not feeling much of an emotional response to a stimulus, you may not show an emotional response either, which is how it’s linked with a flat affect. But in flat affect, you do have an emotional response, although you don’t show it in your face or body.

Emotional blunting is present in many of the same conditions as a flat affect, including:

If you have a flat affect, you may consider treating it. With the appropriate treatment plan in place, this symptom may be treatable and recovery is possible.

It’s highly advisable to reach out to a doctor, neurologist, or mental healthcare professional. A trained professional will be able to determine the underlying cause of your flat affect and provide treatment options.

Treatment will vary according to what caused the flat affect. Options may include:

Medications

If a medication is causing your flat affect, your doctor may change the type of medication you’re taking or the dosage.

If your flat affect stems from a mental health condition, medication may help alleviate several of your symptoms, including a diminished emotional expression.

Psychotherapy

Therapy is considered a first-line treatment in many of the conditions associated with a flat affect.

If you’re not sure where to start, you may find it useful to locate a therapist with our search tools.

Social skills training

For people living with schizophrenia, social skills training can teach you how to express your emotions and body language appropriately for social situations.

Speech therapy

Since a monotone voice is often a sign of a flat affect, this type of training can help you express more emotion using different tones of voice.

Couples counseling or family therapy

At times, a flat affect may interfere with your relationships.

If your loved ones can’t read how you’re feeling all the time, they may find it difficult to know how to connect with you.

Having an intermediary, like a couples counselor or family therapist, may help you sort out any communication problems.

A flat affect could make you feel different from other people, or pose a communication challenge between you and those you love. But flat affect can be managed.

Your treatment plan will depend on what caused your lack of emotional expression. Since there are many possible causes of a flat affect, it’s best to work with a professional.

Most importantly, don’t give up on healing. There is hope for your recovery.