Table of ContentsView AllTable of ContentsOverviewDopamine and Schizophrenia SymptomsImplications for TreatmentWhat Does This Mean for Patients?Causes of SchizophreniaHigh vs. Low DopamineImplicationsSerotonin and Schizophrenia
Table of ContentsView All
View All
Table of Contents
Overview
Dopamine and Schizophrenia Symptoms
Implications for Treatment
What Does This Mean for Patients?
Causes of Schizophrenia
High vs. Low Dopamine
Implications
Serotonin and Schizophrenia
Close
Experts do not fully understand what causes schizophrenia, but evidence suggests that dopamine abnormalities may play a role. High and low levels of dopamine in certain regions of the brain can also affect different symptoms of schizophrenia.
Schizophreniais a debilitating mental disorder with a multitude of symptoms. These can range from disorganized speech and behavior to delusions and hallucinations. Some cases are far more disabling than others, but in most cases, people with this disorder require lifelong treatment and care.
Current research suggests that schizophrenia is a neurodevelopmental disorder with an importantdopaminecomponent.Four decades of research have focused on the role of dopamine in schizophrenia, and it seems clear that excesses or deficiencies in dopamine can lead to schizophrenic symptoms.
At a GlanceWhile other factors also play a role in the development of schizophrenia, dopamine imbalances have been identified as a key factor affecting symptoms. Too much dopamine in key areas of the brain results in delusions and hallucinations (positive symptoms) or cognitive deficits and reduced social/emotional activity (negative symptoms). Understanding the factors that contribute to dopamine symptoms can help doctors treat the condition more effectively.
At a Glance
While other factors also play a role in the development of schizophrenia, dopamine imbalances have been identified as a key factor affecting symptoms. Too much dopamine in key areas of the brain results in delusions and hallucinations (positive symptoms) or cognitive deficits and reduced social/emotional activity (negative symptoms). Understanding the factors that contribute to dopamine symptoms can help doctors treat the condition more effectively.
What Is the Dopamine Hypothesis of Schizophrenia?
The dopamine hypothesis of schizophrenia was one of the first neurobiological theories for this disease.
Dopamine HypothesisThis theory suggests that an imbalance of dopamine is responsible for schizophrenic symptoms. In other words, dopamine plays a role in controlling our sense of reality, and too much or too little can cause delusions and hallucinations.
Dopamine Hypothesis
This theory suggests that an imbalance of dopamine is responsible for schizophrenic symptoms. In other words, dopamine plays a role in controlling our sense of reality, and too much or too little can cause delusions and hallucinations.
The evidence for this theory comes from many sources, including post-mortem studies that have imbalances of dopamine as well as its metabolites in schizophrenic patients.In addition, drugs that block the receptors for dopamine can help control schizophrenic symptoms.
How Does Dopamine Cause Schizophrenic Symptoms?
There are two types of schizophrenia symptoms that an excess of dopamine may cause:positive and negative. Positive symptoms include delusions and hallucinations. Negative symptoms include a decrease in social activity, emotional range, and cognitive function.
Positive Symptoms
Positive symptomsare those that appear to come from outside the person. These can include delusions, hallucinations, or thought disorders.
Dopamine contributes to the development of positive symptoms through its effects on subtype-3A dopamine receptors (D3) of cortical neurons.The subtype-3A receptor is found in the prefrontal cortex, which controls planning, thinking, and other cortical areas.
Negative Symptoms
While positive symptoms appear to come from outside,negative symptomsappear to be internal. These include decreased social activity and emotional range, as well as cognitive deficits like poor problem-solving or memory deficit.
The mechanisms contributing to negative symptoms are linked to dopamine levels in thelimbic system.Dopamine excess leads to an increase in the activity of dopamine receptors, creating overstimulation similar to that seen in positive symptoms.
Some researchers suggest that this overactivity decreasesneuronal inhibition, leading to decreased social behavior and cognitive deficits.
Treatment Implications of the Dopamine Hypothesis
The dopamine hypothesis has important treatment implications. The vast majority of currentantipsychotic medicationstarget dopamine, and this makes sense, given that these drugs were discovered through serendipitous observations of their effect on schizophrenia.
Unfortunately, these medications produce a number of debilitating side effects, most notablyextrapyramidal symptoms(EPS) liketardive dyskinesia. Newer second-generation antipsychotics have fewer side effects, but none are perfect.
Being diagnosed with schizophrenia can be extremely hard on patients and their families. It’s important that doctors and researchers continually investigate new treatments that could improve the lives of people living with this disorder.
However, it’s also important to remember that schizophrenia is a complex disorder, and there are many ways the disease can manifest. Dopamine hyperactivity may not be the primary cause of schizophrenia in all patients. Furthermore, even if dopamine hyperactivity is the primary cause it still doesn’t explain why some patients respond more strongly than others to the same treatment.
How to Choose the Best Type of Therapy For You
Does Too Much Dopamine Cause Schizophrenia?
Increased activity of the mesolimbic pathway is related to positive symptoms of schizophrenia (delusions, hallucinations, etc.). This means that increasing the activity of dopamine receptors in this brain system could theoretically reduce delusions and hallucinations.
As mentioned previously, this is what most modern medications do: they block post-synaptic dopamine receptors in order to reduce psychotic symptoms. Unfortunately, when scientists block all available dopamine receptors they also produce a number of debilitating side effects such as extrapyramidal symptoms (EPS) and tardive dyskinesia.
Is Dopamine High or Low in Schizophrenia?
The most common theory about the cause of schizophrenia is that there are too many dopamine receptors in certain parts of the brain, specifically the mesolimbic pathway.This causes an increase in mesolimbic activity which results in delusions, hallucinations, and other psychotic symptoms.
Implications of the Dopamine Hypothesis
Furthermore, it’s also possible that different patients will respond to treatment differently based on how their disease manifests.
It’s important for healthcare providers and researchers to continue investigating how schizophrenia works in the brain. This will help them develop better treatments for this complex disorder.
Research also implicates serotonin as a regulator of dopamine release.Antipsychotic medications, including olanzapine andclozapine, reduce serotonin activity and increase dopamine activity.
For example, olanzapine-induced reductions in serotonin metabolism were associated with significant improvements in negative and positive symptoms, but not cognitive deficits.
Takeaway
Schizophrenia is a severe mental disorder that can be treated. If you or someone you know was recently diagnosed with schizophrenia, you might be wondering what the future holds. Healthcare professionals can help you manage your symptoms and chart a course for the best possible outcome.
Sometimes, there may be periods of remission that allow you to live a productive life even when coping with schizophrenia. As new treatments are continually being developed, we can look forward to better options for people who experience this disorder in the future.
13 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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