The epidemiology of schizophrenia can tell you about the frequency, patterns, and determinants of this mental health disorder among specific populations.

Epidemiology is the study of health-related patterns as seen across different populations. It uses data-driven, systematic research to identify things such as risk factors, causes, and frequency of disease within groups of people.

Although schizophrenia is considered uncommon, it’s a globally present disorder, and some demographics may experience it more frequently, differently, or sooner than others.

Regularly updating the epidemiology of schizophrenia can help the scientific community continue to learn more about this condition.

The exact scope of schizophrenia globally varies by country and data source, but the World Health Organization (WHO) indicates schizophrenia affects approximately 24 million people (1 in every 300) worldwide.

In the United States, the prevalence ranges between 0.6% and 1.9%.

While anyone can receive a diagnosis of schizophrenia, some patterns have become apparent throughout years of epidemiology research.

Age

Schizophrenia can affect anyone but is most commonly diagnosed in adults versus children. Symptoms most often appear in the late teens through early 30s.

Sex

Research indicates that males and females have a similar lifetime prevalence of schizophrenia, though their susceptibility can be different at certain life stages.

Sexuality and gender

According to a scoping review from 2016, people identifying as LGBTQIA+ may be disproportionately affected by schizophrenia, compared with cisgender people and heterosexuals.

Are sex and gender the same thing?

People often use the terms sex and gender interchangeably, but they have different meanings:

  • “Sex” refers to the physical characteristics that differentiate male, female, and intersex bodies.
  • “Gender” refers to a person’s identity and how they feel inside. Examples include man, woman, nonbinary, agender, bigender, genderfluid, pangender, and trans. A person’s gender identity may be different from the sex they were assigned at birth.

Family history

People with a first-degree relative who has received a diagnosis of schizophrenia are six times more likely to also receive a diagnosis of schizophrenia, according to the National Alliance on Mental Health.

A twin-based study from 2017 suggests the heritability of schizophrenia is 79%.

Race or ethnicity

Black people are more likely to receive a diagnosis of schizophrenia compared with white people. This disparity has been noted multiple times in research, most recently in a 2018 large-scale review of 55 studies.

Researchers found Black people were 2.4 times more likely to receive a diagnosis of schizophrenia compared with white people.

It’s important to note that the Black community experiences many levels of stigma when it comes to mental health care, so these statistics should not be taken without context. Learn more about mental health care in the Black community here.

Do disparities equal higher rates of schizophrenia?

Epidemiology shows us patterns and trends. If people from one population receive a diagnosis of schizophrenia more often than another, it doesn’t necessarily mean they have a higher rate of occurrence.

For example, according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR), evidence suggests that schizophrenia may be overdiagnosed among African American and Hispanic populations.

Many factors can go into why a diagnosis is overused, including quality of healthcare, level of culturally appropriate care, and how likely a population is to seek mental health services in general.

Diagnosis rates can also only account for people who take the step to be seen by medical professionals.

According to a global trends report from 2020, the highest age-adjusted rates of schizophrenia are found in China, followed by the Netherlands and Australia.

The highest rates of newly diagnosed schizophrenia cases are seen in China, followed by India and the United States.

These findings are similar to a 2018 systematic review that found schizophrenia was most prevalent in East, South, and Southeast Asia, Western Europe, and high income North America.

People in other countries often report experiencing schizophrenia differently. For instance, according to a study from 2015, those in India and Ghana more frequently report hearing voices that are supportive or comforting, rather than stressful or disturbing.

Schizophrenia is rarely diagnosed during childhood. It typically develops in the late teens to early 30s for males and between the early 20s and early 30s for females. No research could be found on when schizophrenia presents in intersex individuals, but it’s likely that symptoms will present around their 20s or early 30s as well.

Almost half of all people living with schizophrenia also live with another mental and behavioral health condition.

The DSM-5-TR states comorbidity with substance use disorders is high in schizophrenia, particularly that of tobacco use disorder.

Comorbid obsessive-compulsive disorder (OCD), panic disorder, and other anxiety disorders are also seen but at a lower rate.

There’s no known singular cause of schizophrenia. Structural brain differences, trauma, environmental exposures, and genetics are all potential factors that can contribute to this condition.

Among these, none can be considered “the” primary cause. The DSM-5-TR states the majority of people with risk factors for schizophrenia never develop the disorder.

Schizophrenia is a progressive, lifelong disorder, but life expectancy can vary significantly depending on the age of onset, the country you live in, access to mental health services, and if you’re experiencing suicide ideation.

Overall, schizophrenia carries a higher risk of premature mortality compared with the general population. In the United States, the average rate of premature time lost is 28.5 years of life.

According to the DSM-5-TR, the decreased life expectancy is likely related to medical conditions more common in schizophrenia than in the general population, such as:

These conditions, combined with poor health maintenance behaviors in schizophrenia — like delayed wellness checks, lack of dietary management, and little exercise — can increase the impact chronic diseases have on schizophrenia mortality rates.

Suicidality is also a factor. Approximately 4.9% of people living with schizophrenia end their own lives, compared with approximately 0.01% of the people in the general population.

Schizophrenia support

If you or a loved one have received a diagnosis of schizophrenia or would like to learn more about this condition, support is available every day, all day through the SAMHSA National Helpline at 1-800-662-4357.

By calling this number, you can speak confidentially with a trained representative about schizophrenia symptoms, your concerns, treatment options, or support services in your area.

If you think you may be experiencing a mental health emergency, you can reach emergency responders by dialing 911 or 988 or by calling local emergency services.

Schizophrenia is a mental health disorder that affects approximately 24 million people around the world. It’s more common among adults and regularly co-occurs alongside substance use disorders.

While the epidemiology of schizophrenia shows higher rates in specific populations, the exact reasons behind many of these findings are complex and still under investigation. It’s most likely that a combination of environmental and predetermined factors result in this experience.