How Common Is Schizophrenia?

Schizophrenia is a relatively uncommon but serious mental illness characterized by changes in a person’s thoughts, feelings, and behaviors. It is a chronic brain disorder that can affect a person’s ability to interpret reality. People with this condition often experience hallucinations, delusions, disorganized thinking, and abnormal behaviors. 

How many people are affected by schizophrenia in the U.S. and worldwide? While there is a relatively low prevalence of schizophrenia, it is a serious mental disorder that can cause significant impairment.

Schizophrenia is a serious chronic, lifelong condition. However, it can be managed with appropriate treatment, so it is important to seek help from a doctor or mental health professional if you are experiencing symptoms of this disorder.

Schizophrenia Prevalence

The term prevalence is used to indicate how many people are currently living with a specific condition at or during a particular period of time. It is often used in the field of epidemiology, an area of medicine that seeks to understand disease prevalence, risk factors, and outcomes.

Estimates suggest that less than 1% of people are affected by schizophrenia.

• The World Health Organization reports that 20 million people worldwide have schizophrenia.
• The National Institute of Mental Health (NIMH) suggests that between 0.25 and 0.64% of the U.S. population has schizophrenia and related psychotic disorders. NIMH estimates that the worldwide prevalence of schizophrenia is around 0.33 to 0.75% (among non-institutionalized individuals).

However, it can be difficult to estimate the exact number of people affected by schizophrenia for several reasons. Some factors that influence the ability to gather statistics on the condition are due to the complexity of making a diagnosis, the overlap with other psychiatric conditions, and the number of people who go undiagnosed and untreated. 

Who Is Affected?

Schizophrenia can impact people throughout the entire lifespan, but people are usually diagnosed sometime between late adolescence and their early 30s. Symptoms tend to begin earlier in men than in women, but many of the more subtle signs of the condition may be present for some time before more obvious symptoms begin and a diagnosis is made.

It is also important to note that the condition does not always occur in isolation. Around half of the people who have schizophrenia also have co-occurring mental health or behavioral conditions. 

Research has found that anxiety, depression, and substance use disorders commonly co-occur with schizophrenia. Having a comorbid mental disorder may result in overall poorer quality of life and worse clinical outcomes depending on the nature and severity of the condition. 

Impact

While schizophrenia has a relatively low prevalence, it is linked to significant social, health, and economic issues, which is often referred to as a condition's 'disease burden.' The burden of the disease is an assessment of the societal and individual impact of a condition as measured by a variety of indicators including the impact on individual health, overall mortality, and economic costs associated with the disease.

A study published in The Lancet found that schizophrenia is one of the top 15 causes of disability throughout the world. 

Another study published in JAMA Psychiatry found that the lifespan of those with schizophrenia is shortened by an average of 28.5 years compared to that of the general population. The study looked at adults between the ages of 20 and 64 starting in 2001 and followed up in 2007.

Overall, adults who had schizophrenia were 3.5 times likely to die during those years compared to adults in the general population. The results indicated that the leading causes of death among people with schizophrenia included:

• Cardiovascular disease
• Lung cancer
• Influenza
• Pneumonia
• Accidental death
• Nonsuicidal substance-induced death.

Deaths linked to substance use highlight the possible dangers of comorbid substance use.

While accidental deaths accounted for more than twice as many deaths as suicide, research suggests that almost 5% of people with schizophrenia die by suicide. This rate is much higher than it is for the general population. NIMH notes that this risk of suicide tends to be the highest during the earliest stages of the condition.

Prognosis

WHO reports that people who have schizophrenia are two to three more times likely to die early. This is largely due to preventable physical illnesses such as infections, cardiovascular disease, and metabolic conditions.

Prognosis can be difficult to estimate since mental health experts often have different definitions of what recovery means. One 2013 study suggested that approximately one in seven people with schizophrenia recover, meaning they experience improvements in clinical and social domains lasting at least two years.

Other statistics related to the outlook for schizophrenia include:

• While the condition is treatable, approximately 69% of people who have schizophrenia do not receive appropriate care
• 90% of people who have untreated schizophrenia live in low- or middle-income countries, which often leads to a lack of access to mental health treatment

Another significant barrier to treatment is that people with schizophrenia are less likely to seek out treatment for their condition.

The overall outlook for schizophrenia tends to vary considerably from one individual to the next, but the management of symptoms is possible with appropriate treatment.