What Is The Dopamine Hypothesis Of Schizophrenia?

The cause of schizophrenia is currently unknown. However, experts believe there may be a combination of risks and experiences that contribute to its development. One such factor being studied is the “dopamine hypothesis,” which posits that high levels of dopamine may be connected to the development of schizophrenia. Learning more about this theory may offer insight into the unique connections between schizophrenia, mental health, and neurotransmitters in the brain. Those with schizophrenia can often manage their symptoms with a combination of therapy, medication, and lifestyle changes.

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Understanding schizophrenia: DSM-V criteria

Schizophrenia is a spectrum disorder listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) and International Classification of Diseases, 11th Edition (ICD-11). In the fourth edition of the DSM, the DSM-IV, schizophrenia was classified into subcategories. However, it has since been updated to reflect the spectrum of diverse symptoms and experiences with which individuals may live.

Diagnostic criteria and positive and negative symptoms’ role

Diagnostic criteria for schizophrenia typically include the following: 

• Sensory perceptions that are not genuinely occurring (usually referred to as hallucinations) 
• Strongly held false beliefs (also known as delusions) 
• Disorganized thinking and speech
• Disorganized or catatonic behavior (a loss of movement, speech, and reaction to external stimuli)
• Negative symptoms, such as a lack of emotional expression or withdrawal from social environments and connections
• A significant lack of function in one or more major areas of life, such as relationships or self-care 

To be diagnosed with schizophrenia spectrum disorder, an individual must usually experience positive, negative, and cognitive symptoms for at least six months, with at least one month of active-phase symptoms or a psychotic episode. 

In addition, a diagnostic provider must rule out schizoaffective disorder and bipolar disorder as causes of symptoms. Individuals who were diagnosed with autism spectrum disorder (ASD) in childhood must show psychotic symptoms in adulthood to be diagnosed with schizophrenia. 

What is the dopamine hypothesis of schizophrenia? 

The dopamine hypothesis of schizophrenia is a psychological theory about the potential cause of schizophrenia. It posits that brain chemicals like dopamine may cause some of the imbalances that contribute to this mental health condition. However, there are some controversies around this theory, so reviewing several pieces of evidence may be useful to understand the possibilities. 

The dopamine hypothesis was created due to observations that dopamine-blocking medications could improve symptoms in some people with schizophrenia. Doctors concluded that people with schizophrenia may have higher rates of dopamine release in the brain, which could be a cause of symptoms. However, this finding has not been confirmed as a psychological fact.  

Current research on the dopamine hypothesis of schizophrenia

A 2020 study in the World Psychiatry Journal stated that glutamate and dopamine could play significant roles in neuronal signaling in the prefrontal cortex, which may impact symptoms of schizophrenia. Researchers examined evidence for dopamine dysfunction in schizophrenia, including the following statistics: 

• In examinations of levels of dopamine agonists in cerebrospinal fluid, levels of dopamine transmission are increased in some people with schizophrenia. 
• In postmortem examinations, individuals experiencing psychosis had higher D2 receptor levels and dopamine abnormalities. 
• Dopamine antagonists, like chlorpromazine and reserpine, were found effective in treating schizophrenia and blocking the D2 receptors.

The authors concluded that more studies may be needed to fully understand these connections. In addition, they noted that dopamine levels are typically more associated with positive and psychotic symptoms than negative symptoms, and this hypothesis may not fully explain negative symptoms. 

Controversy on the dopamine hypothesis

The primary controversy related to this hypothesis of schizophrenia is that it does not explain all the symptoms required for a schizophrenia diagnosis, most notably the negative symptoms. In addition, other transmitters may impact schizophrenia, including glutamate, adenosine, and serotonin receptors, and dopamine may not be the only impactful chemical in this process. 

Is there treatment for dopamine abnormalities? 

Dopamine abnormalities in any condition can often be treated with medication and lifestyle changes. However, most of these treatments tend to be focused on dopamine deficiency, which generally refers to levels of dopamine that are too low in the brain and body. Treatments for high dopamine levels might work by blocking dopamine receptors in the brain. If you want to try these treatments, talk to your doctor about potential options. 

Consult a medical doctor before starting, changing, or stopping a medication for any condition. The information in this article is not a replacement for medical advice or diagnosis.

Other treatment options 

Schizophrenia treatments have been widely studied, and several evidence-based options are available, including, but not limited to, the following. 

Antipsychotic medication

Outside of medications that block dopamine receptors in dopamine dysregulation, antipsychotic medications are often prescribed to reduce psychotic symptoms in people with schizophrenia. These medications may stop or reduce hallucinations and delusions, which can help individuals live more independent lives and maintain jobs and relationships. 

Talk to your doctor about the potential for antipsychotic medications in the treatment of your symptoms. Negative symptoms might also be treated with medication, such as antidepressants or anti-anxiety medications.  

Social recovery therapy

Social recovery therapy is a specific therapeutic modality primarily developed to support individuals experiencing first-episode psychosis. Studies have found that this intervention may reduce symptoms and help individuals maintain independence and recovery over the 15 months following the end of treatment. 

This intervention may help individuals with schizophrenia build and maintain healthy relationships and social systems, which has been found vital in improving function levels. 

Support groups 

Support groups may offer a healthy way to find a support system. Being able to communicate with other individuals with schizophrenia can provide a sense that one is not alone in their symptoms. This connection with others can also provide hope by seeing that people going through similar situations are successfully managing symptoms. 

Support groups may offer a safe space to talk about difficult symptoms of psychosis, which are often stigmatized by general society. It may be helpful to look for a support group led by a licensed therapist due to the nature of schizophrenia, as it can cause severe symptoms. 

Lifestyle changes

Lifestyle changes are usually not considered a “treatment,” but they are often used alongside medication and therapy to help people with schizophrenia maintain recovery or remission from episodes. Certain changes that may be helpful include the following: 

• Sleep hygiene: Sleep hygiene practices, like putting devices away an hour before bed, eating nutritious meals a few hours before sleeping, and maintaining a comfortable sleeping environment, can reduce the risk of challenging symptoms. 
• Nutritious eating: Eating foods high in vitamins and nutrients can help the body regulate itself, which may reduce physical symptoms of mental illness and support other healthy habits, like sleep. 
• Exercise: Exercise, including walking, dancing, or swimming, among other options, can help individuals cope with challenging symptoms and increase endorphins in the brain. 
• Spending time in nature: Nature can be calming and inspire creativity, which could be a healthy coping mechanism for people with schizophrenia. 

If you’re unsure how to start making changes in your daily life, consider asking a therapist for help developing a safety plan and daily routine. 

Develop effective coping skills for daily life

Work with a licensed therapist online

Therapy

Therapy can be a helpful way to manage schizophrenia symptoms. With a therapist, clients can reframe delusions, learn to cope with potentially frightening hallucinations, and recover from psychosis healthily after an episode. A therapist can also help individuals with schizophrenia identify symptoms of the prodromal phase (the phase that occurs before an active episode), as well as psychotic symptoms. 

However, some people living with schizophrenia may avoid in-person therapy due to accessibility or financial challenges. In these cases, online therapy through a platform like BetterHelp may be beneficial. Clients can choose a session time that works for them and attend therapy from home or another location with an internet connection. In addition, online platforms may offer valuable tools for support, like worksheets assigned by the therapist to work through challenging behaviors, thoughts, or emotions. 

Studies usually back up the effectiveness of online therapy for individuals with schizophrenia. One study, published in 2015 in HHS Public Access, found that individuals with schizophrenia who tried an online intervention group with their family members typically had lower perceived stress and a higher perceived level of social support after three months of treatment. However, it can be important to note that individuals currently experiencing positive or psychotic symptoms may need to seek care in person.