Flat Affect

Medically Reviewed by Jennifer Casarella, MD on December 03, 2021

Your affect is the outward expression of your emotional state. If you’re happy or upset, people usually can see it on your face and hear it in your voice. But sometimes your emotions and how you express them don’t match up. You may be elated or depressed, but others can’t tell.

This is called a flat affect. People who have it don’t show the usual signs of emotion like smiling, frowning, or raising their voice. They seem uncaring and unresponsive.

Flat affect can be brought on by different conditions.


This is a serious, long-term mental illness. Some symptoms include:

  • Believing things that aren’t real (delusions)
  • Seeing or hearing things that don’t exist (hallucinations)
  • Disorganized thinking or speech
  • Sudden agitation, confusion, and other unusual behaviors

A flat affect can be a negative symptom of schizophrenia, meaning that your emotional expressions don’t show. You may speak in a dull, flat voice and your face may not change. You also may have trouble understanding emotions in other people. You might confuse happy and sad, or misjudge just how happy or sad the other person might be.

Schizophrenia is a lifelong illness. Even if your symptoms have gone away, you’ll need to stay on medication and get therapy. If your symptoms are severe, you may need to go to the hospital for your or other people’s safety.

Social skills training can help change a flat affect. This is when you work with a therapist or other mental health expert to learn how to communicate, interact with others, and manage everyday activities.


A flat effect can be one of the symptoms of this mood disorder. Researchers have used movie clips to study flat affect and depression. In one small study, they found that people who are depressed reacted less to positive scenes than people with schizophrenia did. Depressed people also reacted slightly more to negative clips.

Experts don’t exactly know why depression leads to a flattened affect. They think it may be linked to things such as a problem with your brain chemistry, your genes, and physical changes to your brain.

Traumatic Brain Injury (TBI)

This brain damage can happen after a car crash, a fall, or any other injury that causes a hard hit to the head.

The impact bounces your brain back and forth inside your skull. The trauma causes bruising and bleeding and tears the nerve fibers.

TBI can hurt a part of your brain called the frontal lobe. That’s where emotional expressions start. A damaged frontal lobe may cost you your ability to recognize or feel different emotions. The result is a flat affect. You also may miss cues in other people’s body language. A brain injury can even change your personality.

TBI can range from mild to severe. Your symptoms may go away after a few months or they may last for the rest of your life.

Your doctor will recommend a combination of treatments. A speech therapist or neuropsychologist can help you manage your flat affect and improve your relationships with family and friends.

Autism Spectrum Disorder (ASD)

Scientists know that autism and related disorders stem partly from genetics as well as differences in the brain.

People with ASD interact, behave, and communicate in unusual ways. A flat affect is one of them. Your face often may appear blank. Your voice may not change tone or may sound robot-like. People with ASD also have a hard time reading other people’s voices and body language.

It can be difficult to diagnose conditions like anxiety or depression in people with ASD because they may not give many outward signs. That’s why it’s important for caregivers and doctors to check for changes in sleep, appetite, and overall mood.

There’s no cure for ASD. But medication can help with energy level, focus, depression, and seizures. Working with a therapist can help you better relate to other people.

Show Sources


Brainline: “Flat Affect and Brain Injury.”

Schizophrenia Bulletin: “Flat affect in schizophrenia: Relation to emotion processing and neurocognitive measures.”

Mayo Clinic: “Schizophrenia,” “Depression (major depressive disorder).”

Mayfield Brain & Spine: “Traumatic brain injury.”

CDC: “Signs and Symptoms of Autism Spectrum Disorders.”

Autism Speaks: “What's the connection between autism and depression?”

Journal of Abnormal Psychology: “Emotional Experience and Expression in Schizophrenia and Depression.”

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