Schizophrenia commonly co-occurs with other mental health conditions, including depression. However, experts do not know exactly why this happens.

People with schizophrenia and depression may have false beliefs, see or hear things that are not there, and experience immense psychological pain. Certain individuals may have a genetic predisposition to one or both conditions, while environmental factors may also play a role.

Exact estimates of the prevalence of depression in people with schizophrenia vary significantly from study to study. Partially, this is because distinguishing symptoms of one from the other can sometimes be challenging.

Despite this, researchers know that the two diagnoses share similar risk factors and that similar underlying disease mechanisms may contribute to each.

Read on to learn more about the link between depression and schizophrenia.

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Researchers still do not fully understand the causes of depression or schizophrenia and why they often occur together. Both environmental and genetic factors, and the interaction between the two, can cause either condition.

In genetically vulnerable people, environmental factors, such as trauma or exposure to certain infections, might trigger a mental health condition.

Some potential explanations for the fact that the two commonly appear together include the following:

  • Symptom overlap: Because both schizophrenia and depression share some common symptoms, it is possible that doctors may misdiagnose one as the other. For example, the negative symptoms of schizophrenia, such as anhedonia — the inability to feel pleasure or happiness — could be observable as depression.
  • Triggers: One condition may trigger the other. Living with schizophrenia can be stressful and traumatic, which could lead to symptoms of depression.
  • Risk factors: The two diagnoses share similar risk factors, including exposure to trauma.
  • Genetics: The two conditions may have similar disease pathways in the brain or body. They may also share genetic causes.

People with schizophrenia commonly have other mental health diagnoses, including depression. However, there is no single widely accepted percentage of individuals with schizophrenia who also have depression. The estimated rates vary depending on the study and the study population.

In a 2021 meta-analysis, researchers arrived at a pooled average of 32.6%. This means that across the 18 included studies, the average share of people with schizophrenia who also had major depression was 32.6%.

Another 2020 meta-analysis included 43 studies. The pooled average share of people with schizophrenia with a major depression diagnosis was 28.6%.

People with schizophrenia experience both positive and negative symptoms. For a person to receive a diagnosis, they must have negative symptoms that persist for a signification amount of time within a 1-month period. These include

They also may have negative symptoms, which are when positive thoughts and behaviors are absent. They include:

  • anhedonia
  • flat affect
  • low speech
  • low motivation

These negative symptoms are similar to many depression symptoms, making it difficult to distinguish one from the other. Some common depression symptoms include:

  • feeling sad or unhappy
  • feelings of hopelessness
  • feelings of guilt or worthlessness
  • sleep disturbances
  • thoughts of suicide
  • trouble concentrating
  • weight changes
  • loss of pleasure
  • changes in movement, such as moving very slowly

However, the conditions are distinctly different. A 2018 study found that certain symptoms are more specific to depression than schizophrenia, including:

  • low mood
  • pessimism
  • thoughts of suicide

Speaking very little and a blunted affect — meaning showing little emotion — may be more consistent with the negative symptoms of schizophrenia. Low motivation, low energy, and low ability to feel pleasure were common in both diagnoses.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects if it’s safe to do so.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Find more links and local resources.

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Researchers believe the interaction between genes and environment plays a role in both diagnoses.

Some risk factors for depression include:

  • a major trauma, such as a divorce or the death of a loved one
  • a major life change, such as having a child
  • illness, such as receiving a diagnosis of a chronic or serious illness
  • a family history of depression

Some risk factors for schizophrenia include:

  • a family history of schizophrenia
  • malnourishment in the birthing parent during pregnancy
  • childbirth complications
  • being born in winter
  • stress and trauma
  • living in an urban area
  • cannabis use
  • being from historically marginalized groups

Treating one condition will not treat the other. Therefore, if a person receives a diagnosis of both conditions, a doctor will organize a treatment plan that addresses both.

The standard treatment for schizophrenia is antipsychotic medications to reduce delusions, hallucinations, and atypical thoughts and behaviors. There is some evidence that using atypical antipsychotics at a lower dose may help lower rates of depression in people with schizophrenia.

However, this treatment alone will not treat depression.

People who have true depression — not just negative schizophrenia symptoms — need therapy and antidepressants to manage their symptoms.

Learn more about treatment options for depression and schizophrenia.

Depression can make living with schizophrenia more challenging. Because anhedonia is a common symptom of schizophrenia, depression may go unnoticed in people with schizophrenia.

All people must get comprehensive mental health care for all of their diagnoses. Individuals with schizophrenia who notice new or worsening symptoms should not assume that schizophrenia is the sole cause and should contact a healthcare professional.