Delusional Disorder vs. Schizophrenia: 6 Differences

When people talk about mental health conditions that involve psychosis, you might hear terms like “schizophrenia” or “schizoaffective disorder.” The newest version of the Diagnostic and Statistical Manual of Mental Disorders, called the DSM-5-TR, lists several different types of psychotic disorders. Some are widely recognized, while others — such as delusional disorder — may not be as well known.

In this article, we’ll walk you through what schizophrenia and delusional disorder have in common and how they differ. We’ll also break down the key differences in diagnosis, treatment options, and long-term outlook. If you or someone you love is experiencing symptoms of psychosis, understanding the cause is an important first step toward getting support and feeling better.

What Is Delusional Disorder?

Delusional disorder is a psychiatric condition (a type of mental illness) marked by one or more strong false beliefs, called delusions, that persist for at least one month. These beliefs aren’t based in reality and remain fixed even when there’s clear evidence that they’re untrue. Unlike unusual ideas related to conspiracy theories or cultural traditions, delusions in this disorder are considered false by nearly everyone else. There are multiple subtypes of delusional disorder, each based on the main theme of the false belief.

How Is Delusional Disorder Similar to Schizophrenia?

The main similarity between schizophrenia and delusional disorder is that both involve delusions. Also, they’re both considered a form of nonaffective psychosis. This means that their core symptoms aren’t driven by mood changes, such as depression or mania. Instead, they involve a direct break from reality.

Schizophrenia and delusional disorder also share several effective treatment strategies. In both conditions, antipsychotic medications may be prescribed to help reduce psychotic symptoms, such as delusions.

Cognitive behavioral therapy (CBT) — a type of talk therapy — is also helpful for both. CBT can help people identify and challenge false beliefs, build coping skills, and improve insight.

Psychotherapy, another type of talk therapy, can also help someone recognize and correct distorted thinking patterns.

How Is Delusional Disorder Different From Schizophrenia?

Schizophrenia and delusional disorder have different clinical features (signs and symptoms) and ways doctors tell them apart. Here, we’ll cover a few of the key differences to know about.

1. Delusional Disorder Is Less Common Than Schizophrenia

Schizophrenia affects about 0.5 percent to 1 percent of the population. In the United States, that comes to about 1.7 million to 3.4 million people living with schizophrenia.

Delusional disorder is much rarer. Researchers estimate that this disorder affects only 0.02 percent to 0.2 percent of people. That’s about 68,000 to 680,000 people in the United States.

2. The Range of Symptoms Is Different

Schizophrenia has a broad range of symptoms, grouped into three main categories: positive symptoms, negative symptoms, and cognitive symptoms.

• Positive symptoms (also called psychotic symptoms) include hallucinations (such as hearing voices), delusions, disorganized speech, and difficulty thinking clearly.
• Negative symptoms involve things that are missing from typical behavior, like low energy, lack of motivation, social withdrawal, and limited emotional expression.
• Cognitive symptoms include trouble concentrating, processing information, and using or remembering information in daily life.

In contrast, delusional disorder has a narrower set of symptoms. The main symptom is nonbizarre delusions — false beliefs that could potentially happen in real life, like being followed or cheated on. People with delusional disorder typically don’t have other positive symptoms or signs of thought disorder, disorganized behavior, or cognitive impairment.

3. The Age of Onset Is Different

Schizophrenia tends to show up earlier than delusional disorder. It’s usually diagnosed in late adolescence or early adulthood. Men are about 1.4 times more likely to have schizophrenia than women, according to research in General Psychiatry, and they’re also more likely to be diagnosed at a younger age.

In delusional disorder, the age of onset is later. A diagnosis is usually made between 33 and 55 years of age. However, the age of onset can range from 18 years to 90 years. It may be slightly more common in females.

4. Daily Functioning Is Less Affected in Delusional Disorder

One of the biggest differences between the two mental health conditions comes down to daily functioning. This refers to someone’s ability to live independently, maintain relationships, and hold down a job.

Schizophrenia tends to cause significant impairment across these areas of life. People may struggle with practicing basic self-care, managing routines, or engaging socially due to cognitive and negative symptoms.

In contrast, people with delusional disorder often maintain a high level of functioning. Outside of their delusions, their thinking and behavior may seem completely normal. However, the delusion itself can still cause tension with family members, friends, or coworkers, especially if others take issue with their beliefs. People may become so wrapped up in their delusions that it disrupts their life in some ways, but this is usually more manageable.

5. Causes and Risk Factors Are Different

Schizophrenia is a neurodevelopmental disorder, which means that it starts early and may be linked to genetics and early brain development. Having a family history, brain chemical imbalances, and a history of substance use are known risk factors. Childhood trauma and complications during birth may also increase the risk.

In contrast, delusional disorder often emerges later in life and is more strongly tied to social isolation. Having a language barrier with others or having visual or hearing impairments can all contribute to social isolation. Stress or alcohol use disorder can also contribute to the risk. Researchers think brain changes or certain chemical imbalances in the brain may also play a role, but these are still being studied.

6. The Types of Delusion Are Often Different

Bizarre delusions — beliefs that are clearly impossible or not grounded in reality — are more common in schizophrenia. These might include thinking the government has implanted thoughts into your brain or that your organs have been replaced by machines.

Nonbizarre delusions, on the other hand, involve situations that could technically happen in real life, even if they’re untrue. Examples include believing your spouse is unfaithful or that a neighbor is spying on you. These types of delusions are more typical of delusional disorder. The beliefs may be persistent and deeply held, but the person’s overall thinking remains otherwise logical and well-organized.

When To See a Mental Health Professional

If you’re experiencing unusual or distressing thoughts, hearing or seeing things that others don’t, or holding strong beliefs that seem untrue to everyone else, it’s important to talk to your healthcare team. These could be early signs of a psychotic disorder. Getting help early can make a big difference and may prevent symptoms from becoming more severe.

It’s also important to know that a mental health diagnosis can change over time. This could happen if symptoms become clearer or new ones emerge. If you already have a psychiatrist (mental health specialist), be sure to attend all follow-up visits, even if you feel like things are going well.

Psychiatric disorders are medical conditions. With the right treatment and support, many people live meaningful and fulfilling lives.

Talk With Others Who Understand

On MySchizophreniaTeam, the site for those living with schizophrenia and their loved ones, people come together to gain knowledge about this condition and share their stories with others who understand life with schizophrenia.

Have you or a loved one been diagnosed with delusional disorder? What have been the biggest challenges? Share your thoughts or start a conversation in the comments below.