Diagnosing Schizophrenia: Tests, Symptoms, and Criteria

Diagnosing a mental health condition can be a long, confusing process. This is especially true for schizophrenia, a condition that affects how a person thinks and behaves. Although scientists aren’t entirely sure what causes it, schizophrenia isn’t a rare condition — it affects about 221 in 100,000 people worldwide. In the United States, an estimated 0.25 percent to 0.64 percent of adults have schizophrenia.

If you think you or a loved one might have this condition, it’s important to seek medical help for an evaluation. The sooner schizophrenia is found and treated, the better the chances for managing it well. This article explains what to expect during the diagnostic process.

How Is Schizophrenia Diagnosed?

Schizophrenia is diagnosed differently from many other medical conditions — there’s no single test or scan to detect it. Instead, doctors carefully evaluate a person’s symptoms and behavior based on a set of medical guidelines that list the patterns of symptoms needed for a schizophrenia diagnosis.

Getting a diagnosis of schizophrenia can take time and may require more than one appointment. Doctors also need to rule out other conditions that might be causing the symptoms. This process might involve medical tests such as imaging scans and blood tests.

Schizophrenia Diagnostic Process

During your appointments, your healthcare provider will ask questions to understand your condition. Often, a person with schizophrenia isn’t aware of their symptoms, and family members, neighbors, or friends might be better able to recognize symptoms of schizophrenia. The input of people around you is an important part of the evaluation and diagnostic process.

Current Symptoms

Your healthcare provider will have you describe your symptoms. They’ll ask:

• When your symptoms first started
• Whether certain factors make symptoms worse
• How each symptom feels or affects you

Past Medical History

Your healthcare provider will ask about your medical history, including if you’ve ever been diagnosed with or had symptoms of mental health conditions in the past. If you received any treatment, they’ll need to know what you tried and how well it worked.

They’ll also ask about your overall health, including any medical conditions, treatments, or medications you might be taking. This information can help rule out other causes of your symptoms.

Substance Use

You’ll need to tell your healthcare provider whether and how often you use tobacco, alcohol, or other recreational drugs. They’ll also ask about any prescription drugs you’re taking.

Family History

Although numerous factors can contribute to schizophrenia, there seems to be a genetic link — having a parent or sibling with schizophrenia raises your risk. Your healthcare provider will ask if anyone in your immediate or extended family has had a mental health condition and will want to know about their symptoms and treatment.

Life History

Sometimes, a person’s culture or background can affect their mental health, so your healthcare provider will also ask about your life experiences. You might be asked about your:

• Relationships and children
• Job history
• Cultural background
• Traumatic or stressful life events
• Birth and childhood, including illnesses, accidents, and education

Thoughts of Harm

Your healthcare provider will ask if you have ever thought about hurting yourself, made a plan, or taken action. They may ask if you’ve ever harmed others or had aggressive ideas or behavior, as well as if you have access to potentially harmful items.

Other Tests and Evaluations for Schizophrenia

In addition to talking with you, your healthcare team will perform medical tests to rule out other possible causes of your symptoms. They may start with a physical examination, checking your blood pressure and heart rate. They might also gently feel your abdomen and listen to your heart and lungs.

Blood Tests

Your healthcare provider may order blood tests to check for low iron levels or problems with your organs. For example, thyroid issues can sometimes cause mood changes or problems with thinking and concentration that look like signs of schizophrenia.

Brain Tests

If there’s evidence of a neurological (brain-related) disorder, you might have an electroencephalogram (EEG) done. This painless test checks the electrical activity in your brain. Imaging scans, such as an MRI or CT scan, might also be done to get detailed pictures of your brain.

Drug Screen

A drug screen may be done to check for substances that could be affecting your mood, thinking, or behavior.

Observational Tests

Your healthcare team will watch how you act during appointments. This helps them understand how your symptoms affect your behavior. For example, people with schizophrenia might:

• Use unusual body language
• Speak in ways that are difficult to understand
• Show emotions differently from most people

What Are the Diagnostic Guidelines for Schizophrenia?

To diagnose schizophrenia, healthcare professionals use the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR). According to these guidelines, a person must have at least two of the symptoms listed below for most of one month. The symptoms must also continue for at least six months. At least one of the symptoms must be among the first three of these diagnostic criteria:

• Delusions — Strong beliefs that aren’t true, even when there’s clear evidence against them — for example, believing the TV is sending them messages
• Hallucinations — Seeing, hearing, smelling, tasting, or feeling something that isn’t there, such as hearing voices that others don’t
• Disorganized speech — Speaking in a way that’s jumbled or hard for others to understand
• Disorganized behavior — Acting in increasingly unpredictable and unusual ways
• Negative symptoms — Withdrawing from others, losing interest in daily life, or feeling emotionally flat or disconnected

The DSM-5-TR also states that there must be a decline in a person’s ability to function in daily life, such as at work or in relationships. The symptoms can’t be explained by substance use, medications, or other medical conditions.

What Other Conditions Can Cause Symptoms Similar to Schizophrenia?

Other mental health disorders can have symptoms that look like schizophrenia. These include bipolar disorder and related conditions such as schizoaffective disorder. Some disorders with similar symptoms are grouped as “schizophrenia spectrum disorders.”

Neurological conditions such as Alzheimer’s and other types of dementia can also mimic schizophrenia symptoms. Exposure to certain substances, including heavy metals like lead, can cause symptoms similar to schizophrenia.

Because these symptoms can overlap, it’s possible to be misdiagnosed at first. Diagnoses can change over time as more symptoms appear. If you or a loved one is diagnosed with schizophrenia, your healthcare team will walk you through the next steps and your treatment plan.

With the right support and treatment, many people living with schizophrenia can manage their symptoms and lead meaningful lives.

Talk With Others Who Understand

On MySchizophreniaTeam, the site for people with schizophrenia and their loved ones, people come together to ask questions, give advice, and share their tips with others who understand life with schizophrenia.

What was the diagnostic process like for you? What questions did your doctor ask? Share your experiences in the comments below.