Schizophrenia

Schizophrenia is a serious disorder, and it is more common than many might assume. Most sources say that it affects about 1 in 300 people worldwide, but some estimate that it affects more than 1 in 100 in the United States. Individuals face a higher risk of developing schizophrenia due to the following reasons: 

• Genetics: Having a biological parent or sibling with the condition.
• Environmental factors: Prenatal exposure to viruses or malnutrition, or living in conditions marked by poverty, danger, or stress.
• Substance use: Using certain recreational drugs frequently, especially during teen and adolescent years.

Schizophrenia has heritability of 70 to 80 percent, meaning that up to 80 percent of the risk for developing schizophrenia is due to genetics. Specifically, the disorder is often linked to variations in which genetic material is deleted or duplicated. A tiny deletion in a region of chromosome 22, called 22q11, has been identified as contributing to a small percentage of schizophrenia cases. 

Many people who have symptoms of schizophrenia do not realize that they have a condition that requires medical attention, and family or friends often need to intervene to get them help. The most common symptoms include the following: 

• Delusions (maintaining strong beliefs that aren’t based in reality)
• Hallucinations (seeing, hearing, or sensing things that aren’t there)
• Psychosis (disorganized thinking or behavior, ranging from childlike silliness to unwarranted agitation)
• Disorganized speech (for example, combining unrelated words in ways that can’t be understood)
• Intense fear and paranoia
• Showing little emotion
• Speaking in monotone
• Reduced motivation to socialize or enjoy activities

If someone you know is experiencing these symptoms, it’s important to be supportive, speak with them about your concerns, and encourage them to consult a medical or mental health professional. Males most often notice symptoms beginning in their early 20s, and females beginning in their mid-20s to early 30s. Receiving treatment early, when symptoms start to appear, can help patients better manage those symptoms over time. This can also help prevent more serious long-term complications, such as anxiety disorders, depression, social isolation, alcohol or drug use, aggressive behavior, money problems, being unable to work or attend school, and suicidal ideation or attempts. Over time, schizophrenia can cause subcortical structures of the brain to shrink, most notably the amygdala (associated with threat assessment and fear), hippocampus, and thalamus.

In early stages, before symptoms like delusions, hallucinations, and disorganized thinking develop, other symptoms can resemble those of depression—for example social withdrawal, decreased motivation and scholastic performance, sleep disturbances, irritability, or sadness. Adults with schizophrenia are more likely to experience delusions, while teenagers with the condition are more likely to experience hallucinations. 

Psychologists and other health care providers diagnose schizophrenia primarily by evaluating symptoms, observing behavior, considering medical history, and asking questions based on the criteria in the Diagnostic and Statistical Manual of Mental Disorders. Diagnosis most frequently occurs during a person’s late teenage years to early adulthood, but it is sometimes diagnosed earlier or later in life. 

It can be difficult to identify schizophrenia in teenagers, because early symptoms resemble experiences common among people of that age, including withdrawing from friends and family, not doing well in school, difficulty sleeping, irritability or depression, and reduced motivation. The symptoms can also resemble those that result from the recreational use of marijuana, cocaine, methamphetamines, or hallucinogens. 

There are currently no tests to confirm schizophrenia, but doctors may perform certain tests to first rule out other conditions before making an official diagnosis. These tests may include CT or MRI imaging to check for stroke, brain injury, tumors, or structural changes; lab tests of blood, urine, or cerebrospinal fluid to check for infections, poisoning, or another type of chemical imbalance; and an electroencephalogram (EEG) to check brain activity for a condition such as epilepsy.

Because the exact cause of schizophrenia is still unknown, treatments focus on managing symptoms. Patients should expect to meet with health care providers on a regular basis. Often the severity of schizophrenia symptoms varies over time, with flare-ups in recurring cycles. Hospital stays may be necessary during crisis periods for patients’ safety. Hospital staff can also assist in ensuring that they eat right, get enough sleep, and bathe regularly. 

Schizophrenia is typically treated with antipsychotic medications, which are drugs that block dopamine receptors or target dopamine and serotonin receptors. Additionally, a newer class of antipsychotics is increasingly being used in treatment. This type of medication works through the cholinergic system, which uses the neurotransmitter acetylcholine for various tasks including memory, thinking, and movement. Antipsychotic medications can have various side effects, and it can take some trial and error to find the appropriate drug, but doctors want to manage symptoms at the lowest possible dose. Antidepressants, mood stabilizers, and antianxiety drugs can sometimes be helpful as well. Medication should be used as prescribed, which in most cases means continuing to take them even if symptoms have subsided.  

If medications do not improve the symptoms, doctors sometimes recommend noninvasive electroconvulsive therapy (ECT), which sends brief electrical stimulation to the brain to trigger a controlled seizure. This technique can also be effective for severe depression and bipolar disorder. 

Patients with schizophrenia can also benefit from individual talk therapy, such as cognitive behavioral therapy for psychosis (CBTp). This approach can help individuals better understand how their thoughts influence their behavior and learn healthy coping skills, such as methods to reduce stress. Psychologists may also provide social skills training or therapy for families to help them better understand schizophrenia. Rehabilitation services can further help patients become more resilient, better able to cope with the challenges of the disorder, and more successful at finding and keeping jobs. 

Sometimes patients respond well to treatment but still struggle with ongoing challenges like thinking clearly and staying focused. Without treatment, people with schizophrenia can experience serious problems up to and including a higher risk of suicide. Fortunately, by working with doctors and therapists, patients can often manage symptoms with minimal disruption to their everyday lives. 

The exact cause of schizophrenia remains unknown, but researchers have identified that it likely comes down to a mix of genetics, brain chemistry, and environmental factors. They have identified that schizophrenia coincides with changes to neurotransmitter levels, including dopamine and glutamate, and neuroimaging shows physical changes to the brain structure and central nervous system. Researchers believe that learning more about risk factors will help lead to earlier diagnosis and treatment. 

In 2025, scientists at Stanford Medicine examined massive public datasets to identify the specific types of brain cells involved in schizophrenia, based on gene expression. They determined that a small number of cell types in the amygdala, hippocampus, and thalamus are most likely involved in the disorder (these are the same regions that tend to shrink in schizophrenia-affected brains). This insight has potential to inform future diagnosis and drug development. 

Reading scientific studies

New to research? Read our guide, How to Read a Research Study, to learn some tips for reading scientific publications and interpreting results.