Schizophrenia & depression

Schizophrenia and depression are each distinct mental health conditions. In some cases, a person may experience both schizophrenia and depression.

What is schizophrenia?

Schizophrenia is classified as a psychotic disorder, meaning that it leads to disturbances in thoughts and perceptions. A person who lives with schizophrenia may experience hallucinations, which involves seeing, hearing, tasting, smelling, or feeling things that are not actually present.

They may also experience delusions, which are strange beliefs that persist, even when the person is presented with evidence that the belief is not true. Schizophrenia is also linked to incoherent speech patterns, strange behavior, and negative symptoms, which include social withdrawal, lack of motivation, and blunted emotion ^[1].

What is depression?

Depression, also known as major depressive disorder or major depression, is a mood disorder in which a person experiences deep and chronic feelings of sadness, as well as a loss of interest in their usual activities. Individuals who experience depression may struggle with low energy levels and have a difficult time concentrating.

Other common symptoms of depression are sleep problems, which can include sleeping too much or too little, and changes in weight, which can include either weight loss or weight gain. People with depression may also experience feelings of worthlessness and thoughts of suicide ^[2].

What is the link between schizophrenia and depression?

In some cases, schizophrenia may co-occur with depression. This means that a person has a diagnosis of both schizophrenia and depression. It can also mean that a person experience some episodes of depression throughout their lifetime, while also being diagnosed with schizophrenia.

Some research suggests that depression is common in patients with schizophrenia and related disorders. In fact, there is evidence showing that up to 80% of people with psychotic disorders experience some form of depression ^[3].

In some cases, a person who shows psychotic symptoms along with depression may have schizoaffective disorder. This is a mental health disorder in which a person experiences the psychotic symptoms of schizophrenia, as well as symptoms of a mood disorder, which could include depression.

For a person to be diagnosed with the depressive type of schizoaffective disorder, they must show symptoms of depression for most of the time that they experience psychotic symptoms. Furthermore, they must have a period of at least two weeks during which they show psychotic symptoms without symptoms of depression ^[4].

It is also possible for symptoms that look like schizophrenia and depression to occur in patients who have depression with psychotic features. In this presentation of depression, a person most often experiences psychotic features in the form of delusions that center on the belief that something bad is about to happen ^[5].

Schizophrenia vs. Depression: Symptoms

Schizophrenia and depression are distinct psychiatric disorders, but there are some similarities between the two.

Differences between depression and schizophrenia

The primary difference between depression and schizophrenia is that depression is a mood disorder, whereas schizophrenia is a psychotic disorder. Schizophrenia is primarily characterized by the following symptoms ^[1]:

• Hallucinations (seeing, hearing, feeling, tasting, or smelling things that are not actually present)
• Delusions (beliefs that are maintained even when there is evidence that they are not true)
• Incoherent speech patterns
• Disorganized behavior, such as strange movements or catatonic behavior
• Negative symptoms (lack of speech, low motivation, social withdrawal)

On the other hand, depression involves ^[2]:

• Sad or depressed mood
• Sleep disturbances, such as sleeping less than usual, or sleeping too much
• Gaining or losing weight due to appetite increases or decreases
• Lack of energy
• Loss of interest in or pleasure with usual activities
• Difficulty concentrating
• Changes in movement patterns, which can include either pacing (psychomotor agitation) or lack of movement (psychomotor retardation)
• Feeling worthless or guilty
• Thoughts of suicide

Similarities between depression and schizophrenia

While depression and schizophrenia are different disorders, sometimes they may appear similarly. For example, the two disorders may have the following features in common:

• Negative symptoms in schizophrenia can look likesome of the symptoms of depression. For instance, a person who is experiencing depression may stop participating in their usual hobbies because of a loss of interest in those activities. Similarly, a person experiencing negative symptoms of schizophrenia may withdraw socially or stop engaging in goal-directed behavior.
• Both schizophrenia and depression are associated with changes in movement patterns. A person who is depressed may show psychomotor agitation, which generally involves pacing behaviors. Schizophrenia can also lead to odd movement patterns, such as stayingin uncomfortable postures for an extended length of time. The lack of movement that can come with the negative symptoms of schizophrenia may also mirror the psychomotor retardation seen with depression.
• Finally, some symptoms of depression can appearsimilar to the negative symptoms of schizophrenia. For example, negative symptoms of schizophrenia can cause difficulty with thinking and concentration, and a person may appear to lack energy. These symptoms can mirror some of the diagnostic symptoms of depression.

Can depression cause schizophrenia?

Depression and schizophrenia can occur together, but that does not mean that depression directly causes schizophrenia. There seems to be an overlap between depression and the positive symptoms of schizophrenia. Negative symptoms of schizophrenia, particularly those related to lack of motivation and interest in usual activities, have also been found to be linked to depression ^[3].

Some research shows that symptoms of depression may precede the psychotic symptoms in schizophrenia, suggesting that mood disturbances could be a risk factor for developing schizophrenia. However, the research is inconclusive. There could also be differences in brain structure and functioning that increase the risk of both depression and schizophrenia ^[6].

Can schizophrenia cause depression?

As with depression causing schizophrenia, it is difficult to claim that schizophrenia directly causes depression. However, there is a strong link between schizophrenia and depression.

For example, studies show that patients with depression are at high risk of developing psychotic symptoms. Furthermore in response to the psychological trauma of the episode, people may experience depression following a psychotic episode of schizophrenia ^[6]. In summary, schizophrenia increases the risk of experiencing depression.

Treatment for depression and schizophrenia

Since depression and schizophrenia can occur together, it is important to understand how these two mental disorders are treated. When patients experience comorbid depression and schizophrenia, the best course of treatment is to simultaneously treat depression and schizophrenia ^[3].

Treatment for schizophrenia and depression is likely to include the common components ^{[1] [2] [4]}:

• Antipsychotic medications: Antipsychotics such as aripiprazole, olanzapine, risperidone, quetiapine, asenapine, lurasidone, sertindole, ziprasidone, brexpiprazole, and molindone are routinely used in the treatment of schizophrenia.
• Antidepressant medications: There are several types of antidepressant medications that can be used to treat depressive symptoms. These can include Selective serotonin reuptake inhibitors (SSRIs), Serotonin/norepinephrine reuptake inhibitors (SNRIs), Atypical antidepressants, Serotonin-Dopamine Activity Modulators (SDAMs),Tricyclic antidepressants (TCAs), and Monoamine oxidase inhibitors (MAOIs).  SSRIs, such as escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline are often the first choices for treating depression.
• Therapy: Both schizophrenia and depression are treated with various forms of therapy. This can include individual, group, and family therapy. Group sessions can help people to learn more about their mental health condition and gain support from others experiencing similar challenges. Family therapy can help family members learn how to best support their loved one who has a mental illness. A type of therapy called cognitive behavioral therapy (CBT) can be helpful in both the treatment of depression and schizophrenia, as it can help people to correct unhelpful thinking patterns.