The symptoms of bipolar disorder and schizophrenia vary and can differ in type and severity.

They may get worse and then significantly improve or go into remission for a period of time.

People with bipolar disorder frequently experience extremes in mood. Healthcare professionals may classify “highs” as mania or, in less severe cases, hypomania. “Lows” involve a decrease in mood and, often, depression.

There are three main types of bipolar disorder, although some people have a different arrangement of symptoms:

• Bipolar I: The most intense type. It features episodes of mania and, often, depression that can last at least 1 or 2 weeks at a time. In some cases, a person can experience both states simultaneously.
• Bipolar II: This slightly less intense form involves major depression that can last for weeks, as well as bouts of hypomania that may last several days or more. The two may alternate rapidly or have stretches of time in between them.
• Cyclothymia: This features alternating periods of lower grade depression and hypomania that can last weeks. It may also involve emotional dysregulation and anxious, impulsive, reactive behavior, according to a 2017 review. Mood changes are less dramatic but are never stable for more than 2 months.

All three conditions may include periods of stability.

Symptoms of mania

Mania can involve:

• irritability
• difficulty sleeping or less need for sleep
• excessive energy and restlessness
• high self-esteem
• expansive mood
• inability to concentrate or make decisions
• increased engagement in pleasurable activities, such as sexual activity or drug use
• intense excitement
• racing thoughts
• reckless behavior, such as overspending

In a person with bipolar I or II, depressive symptoms are the same as those in major depressive disorder.

Symptoms of depression

The primary symptom of depression is a feeling of either sadness or hopelessness that persists for 2 weeks or longer. But depression can also cause a significant loss of interest or pleasure in most daily activities.

Other symptoms include:

• changes in appetite
• changes in sleep habits
• fatigue and low energy
• low self-esteem
• physical aches and pains without an apparent cause
• suicidal thoughts or behaviors

Bipolar disorder can also present with anxiety or episodes of psychosis, during which a person loses touch with reality.

When people display symptoms of psychosis, healthcare professionals may be unsure whether they have a type of bipolar disorder or schizophrenia.

Schizophrenia symptoms affect a person’s thoughts, emotions, and behaviors. They include:

Delusions

These are false beliefs, and most people with schizophrenia experience them.

For example, people may think that they are famous or special in a certain way, that they are being harassed or stalked, or that something terrible is about to happen.

Hallucinations

During a hallucination, people see, hear, feel, taste, or smell things that are not there. The most common type of hallucination involves hearing voices.

Disorganized thinking and speech

People exhibiting these symptoms may not make sense when communicating with others. They may give unrelated answers to questions, or their sentences may seem meaningless to the people around them.

Unusual behavior

People with schizophrenia can demonstrate unpredictable behavior. For example, they may act childlike, assume strange postures, or move constantly.

Inability to function as usual

Schizophrenia can affect a person’s ability to take care of their personal hygiene, engage with others in socially acceptable ways, or perform everyday activities.

The following symptoms may occur in either bipolar disorder or schizophrenia:

Episodes of psychosis

For some people with bipolar disorder, an episode of mania or depression can give rise to hallucinations or delusions.

Disorganized thinking

This is common among people living with schizophrenia, but people with bipolar disorder may also seem to have disorganized thoughts. During episodes of mania, a person may have difficulty concentrating on a single idea or task.

Symptoms of depression

During periods of depression, people with either condition may demonstrate a loss of interest in things they once enjoyed. Some people may feel like they cannot experience pleasure or may have trouble concentrating or making decisions.

Some researchers report high rates of drug and alcohol misuse among people with schizophrenia, bipolar disorder, or depression.

If a person has significant symptom overlap, they may receive a diagnosis of schizoaffective disorder, a related but separate mental health condition.

Bipolar disorder is more common than schizophrenia.

Bipolar disorder affected about 40 million people worldwide in 2019, while 24 million people — about 1 in 300 adults — were living with schizophrenia at that time.

Statistics from the National Institute of Mental Health (NIMH) suggest that approximately 2.8% of U.S. adults experience bipolar disorder in a given year and 4.4% experience it at some point in their lives. Among those, 82.9% have serious impairment due to their symptoms and 17.1% have moderate impairment.

Symptoms of bipolar disorder usually start to appear around age 25, and the condition affects males and females equally.

The NIMH notes that it is difficult to know precisely how many people live with schizophrenia because the diagnosis is complex and symptoms overlap with those of other conditions. In addition, diagnostic criteria vary. Some figures suggest that schizophrenia affects less than 1% of the U.S. population, while advocacy groups say it could be 1.6% or more.

Symptoms typically appear from late adolescence to the early 20s in males and in the late 20s to mid-30s in females.

The experience and likelihood of having bipolar disorder or schizophrenia can vary depending on factors such as a person’s family history and race or ethnicity.

Family history

Having a family member with bipolar disorder or schizophrenia does not mean that someone will definitely have the same diagnosis.

Experts do not know precisely what causes these conditions, but researchers have pinpointed a number of genetic variants in people with these diagnoses. The odds of having either condition increase when a parent or sibling has it.

Brain structure, environment, lifestyle, trauma, and other stressors may further influence the development and intensity of these conditions.

Race and ethnicity

Research suggests that Black Americans receive diagnoses of schizophrenia at up to four or five times the rate that white Americans do. Among Latino American or Hispanic Americans, diagnosis rates are up to three times as high as those of white Americans.

One small 2010 study found that Asian and Latino individuals were more likely to receive a diagnosis of bipolar I disorder than white individuals.

Researchers are not exactly sure why this occurs, but some have suggested that trauma, stress, or marginalization may contribute to the emergence of such conditions.

However, other experts say that there is no difference in the prevalence of bipolar disorder and schizophrenia among those of different racial or ethnic backgrounds. Instead, people may receive a misdiagnosis of a more severe condition when health professionals are biased or unable or unwilling to make an accurate diagnosis.

For example, a Black American may receive a diagnosis of schizophrenia when their symptoms more closely represent major depression or the mania associated with bipolar I disorder. Healthcare disparities among People of Color can amplify these issues and lead to insufficient diagnosis and treatment.

Following strict diagnostic criteria can help health professionals determine whether a person has a particular condition. Broader clinical training can help reduce ethnocentric bias.

Medical professionals use the same procedures to diagnose bipolar disorder and schizophrenia. The process typically involves:

A physical examination

This helps determine whether medical problems are causing psychological symptoms. It can include:

• blood tests
• MRI or CT scans of the brain
• drug and alcohol screenings

A psychological evaluation

Healthcare professionals — usually psychiatrists — look for signs and symptoms of bipolar disorder and schizophrenia, examining anything that affects a person’s thoughts, emotions, and behaviors.

They may ask a person about their personal and family mental health history and have them complete a psychological self-assessment form.

During this evaluation, healthcare professionals will closely observe the person’s appearance and actions.

They will then compare the person’s symptoms with the criteria in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR).

Diary of symptoms and moods

People who may be experiencing schizophrenia or bipolar disorder may wish to keep a daily diary of their thoughts, moods, and sleep habits. Healthcare professionals can use this to identify patterns in their behavior and to spot other clues that inform diagnosis and treatment.

What are the criteria?

Here are some features that can help distinguish the different types of bipolar disorder:

• Bipolar I: at least one episode of mania
• Bipolar II: hypomania with a major depressive episode
• Cyclothymia: episodes of low level depression and hypomania that occur at least half the time over 2 years or longer

The criteria for schizophrenia vary, but according to the DSM-5-TR, a person may receive a diagnosis of schizophrenia if they have two or more of the following for a significant amount of time during a single month:

• delusions
• hallucinations
• disorganized speech
• grossly disorganized or catatonic behavior
• negative symptoms, such as reduced speech or lack of motivation
• social or occupational dysfunction lasting at least 6 months, including at least 1 month of symptoms

A doctor also needs to ensure that a person’s symptoms are not due to any other condition.

Both conditions require lifelong treatment.

Treatment for bipolar disorder

Many people with bipolar disorder require medication to stabilize their moods.

This can include:

• lithium, a mood stabilizer that may help prevent relapse and manage symptoms
• atypical antipsychotics
• anticonvulsants

Psychotherapy is an important part of bipolar disorder management. It may take place individually or in a group or family setting.

Therapy can help people manage their thoughts and emotions, establish routines, and identify triggers.

Those whose condition does not respond to medications or psychotherapy may benefit from electroconvulsive therapy (ECT). The goal of this treatment is to change the brain’s chemistry by sending electrical currents through it, causing a seizure.

Other strategies that can help people with bipolar disorder include:

• avoiding alcohol and drugs
• eating a balanced diet
• exercising regularly
• getting enough sleep
• managing stress
• seeking help and support from family, friends, and others

Bipolar disorder can vary widely, and the symptoms can change over time. A doctor will tailor treatment to suit the individual and may change the approach over time.

Treatment for schizophrenia

Antipsychotic medications are a vital part of treatment for most people with schizophrenia. Healthcare professionals believe that these medications change the brain’s chemistry and reduce symptoms such as hallucinations and delusions.

Some individuals require other medicines, such as antidepressants or antianxiety drugs. Some doctors may also use ECT to improve symptoms of psychosis.

When the person is able to manage the symptoms of psychosis, they can often benefit from psychological and social interventions, which may include:

• psychotherapy in both individual and family settings
• social or behavioral skills training to improve interactions with others
• employment support to help them secure or perform a job more easily
• daily living support to help them find housing and manage daily responsibilities

Other coping strategies include:

• avoiding alcohol and drug use
• joining a support group
• learning about schizophrenia
• maintaining certain lifestyle habits, such as eating a balanced diet, exercising, and following a sleep schedule
• managing stress through strategies such as meditation, exercise, and yoga
• seeking help from family and friends

Although bipolar disorder and schizophrenia have similarities, they also have key differences, especially when it comes to symptom severity and treatment.

People with bipolar disorder generally alternate between periods of high and low moods, while people with schizophrenia typically lose touch with reality as they experience hallucinations and delusions.

With treatment, a person who has either condition can manage their symptoms and reduce the condition’s impact on their life.

Bipolar disorder is typically more manageable after a person receives appropriate treatment. Schizophrenia is more challenging to treat, and people who have it tend to need greater support.