In the United States, about 1.1 percent of adults, or 2.4 million people, have schizophrenia, according to the National Institute of Mental Health. With schizophrenia, you may have hallucinations, such as hearing or seeing things that do not exist, delusions and abnormal thinking. Schizophrenia may also affect social functioning, motivation and emotions. One biological theory of schizophrenia is the dopamine theory, in which the symptoms result from overactive dopamine. The dopamine receptors are the areas in your brain that the neurotransmitter dopamine binds to, and different dopamine receptors have a connection to schizophrenia.
Types
The Lundbeck Institute lists two types of dopamine receptors linked to schizophrenia: D1 class and D2 class. The D2 dopamine receptor's responsibility in the brain is to inhibit the activity of adenylyl cyclase, a type of enzyme. The D1 dopamine receptor stimulates that enzyme and is the most prevalent type of dopamine receptor in the brain, according to the National Center for Biotechnology Information. The D2 dopamine receptor's connection to schizophrenia includes mutations of the gene that encodes the receptor and a rise in the receptor's activity in the prefrontal cortex. The D1 dopamine receptor's connection to schizophrenia includes a lower number of the receptors in the brain, which may cause an increase in the neurotransmitter's concentration.
Medications
Several medications for schizophrenia target these dopamine receptors. Antipsychotics for schizophrenia fall into two groups: typical antipsychotics and atypical antipsychotics. Examples of typical antipsychotics include haloperidol, chlorpromazine and pimozide. Examples of atypical antipsychotics include risperidone, clozapine and olanzapine. Williams College notes that typical antipsychotics target the D2 receptors, while atypical antipsychotics target D3 and D4 receptors instead, which are part of the D2 receptor class.
Effects
The University of Washington notes that medications that target the dopamine receptors support the dopamine theory of schizophrenia. For example, when these medications block dopamine, symptoms reduce. Side effects of antipsychotics are similar to the symptoms of Parkinson's disease, a neurological disorder in which the dopamine-producing cells in the brain become damaged.
Dietary Options
While the nutritional treatments for schizophrenia do not affect the dopamine receptors, they do play an indirect role. For example, the University of Michigan Health System lists folic acid and vitamin B6 as minerals and vitamins that may decrease the symptoms of schizophrenia. Both of these substances are needed for the manufacturing of dopamine, notes the Franklin Institute. You may benefit from a combination of an herb and medication that targets the dopamine receptors. Taking 250mg of ginkgo biloba extract per 2.2 lbs. of body weight with haloperidol increases the drug's effectiveness and helps with side effects, according to the University of Michigan Health System. Talk to your doctor before starting any supplements for schizophrenia.
Considerations
While evidence exists that dopamine plays a role in schizophrenia, evidence also exists that dopamine is not the only neurotransmitter that influences the disorder. For example, clozapine blocks both dopamine and serotonin receptors, notes the University of Washington. When given 2 to 8g of L-tryptophan, a supplement that converts to serotonin, along with 100mg of vitamin B6 each day, patients experience a decrease in agitation and anxiety, according to the University of Michigan Health System. Consult your doctor before beginning any supplements to decrease schizophrenia symptoms.
References
- National Institute of Mental Health: The Numbers Count: Mental Disorders in America
- University of Washington: Schizophrenia
- Lundbeck Institute: Schizophrenia -- Aetiology
- University of Michigan Health System: Schizophrenia
- The Franklin Institute: The Human Brain -- Proteins
- Williams College: Dopamine Receptor Blockade: Antipsychotic Drugs
