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Brain and nervous system abnormalities play a role in many health conditions, particularly mental health conditions. In the case of the psychiatric disorder schizophrenia, deficiencies and excesses in certain neurotransmitters — namely dopamine, serotonin, and glutamate — that relay information in the brain may help facilitate the condition’s development. Due to the complexity of this disorder, the involvement of neurotransmitters in schizophrenia is likely part of a larger mental illness foundation that also includes brain structure abnormalities, genetic predisposition, and environmental stressors.
Neurons are the brain cells that facilitate thinking, movement, and any other command the brain gives the body. In order to carry out their tasks, neurons must communicate with each other. They accomplish this task via neurotransmitters. Some neurons release these chemical messengers, and the neurotransmitters then attach to and influence the activities of other neurons. When this process is functioning properly, the neurotransmitters act as a sort of carrier pigeon between cells, often returning to the original cells when the message is delivered.
Mental disorders as a whole are often misunderstood, but schizophrenia, while one of the more familiar disorders, is also ironically one of the most misunderstood. Many varieties and symptoms of schizophrenia exist, but perhaps the most general definition for the disorder is disorganization of thought and behavior. Some individuals may see or hear things that are not present, and others may hold delusional false beliefs about themselves or the world as a whole. Forms of schizophrenia may further impact emotional expression, speech, and even hinder normal movement.
The neurotransmitter dopamine is heavily involved in an individual’s thought processes and his or her movement as well. Therefore, many researchers hypothesize that this neurotransmitter could potentially be a major factor in schizophrenia. More specifically, elevated levels of dopamine in the brain could underlie many symptoms of schizophrenia.
Scientific evidence has supported the role of dopamine neurotransmitters in schizophrenia. For one, brain scans of schizophrenics often show significantly increased activity in dopamine areas. In addition, pharmaceuticals and conditions that increase dopamine levels often induce symptoms that very much resemble schizophrenia indicators. For example, overuse of amphetamine drugs can cause both paranoia and hallucinations. These drugs merely suggest to the brain that it has an overabundance of dopamine, which indicates the power of these particular neurotransmitters in schizophrenia.
Another strong piece of evidence for the defective neurotransmitters in schizophrenia link rests in common schizophrenia treatment protocols. One of the most frequently used and successful drugs for schizophrenia treatment is clorpromazine. The drug’s main function is inhibition of dopamine receptors in the brain.
Potential causes for this neurotransmitter abnormality are largely theoretical. One proposed theory is simple overproduction of dopamine. Others believe that dopamine production is normal, but the substance cannot be broken down properly. Autopsies of schizophrenic individuals have indicated that the afflicted possess more dopamine receptors than the average, and these receptors may be more sensitive to the neurotransmitter in comparison to other individuals.
Some schizophrenia development theories hint at a link between the serotonin neurotransmitter and schizophrenia as well. Like dopamine, serotonin can impact cognitive functioning, in addition to other behavioral responses relating to mood and impulse control. These responses are often abnormal in schizophrenics, suggesting that there is a contributory link of serotonin neurotransmitters in schizophrenia development. One theory speculates that high combined serotonin and dopamine levels create so-called positive schizophrenia symptoms like auditory hallucinations, whereas a low level of these neurotransmitters might lead to negative symptoms such as blunted emotional reactions. Schizophrenia treatment drugs ranging from clozapine to risperidone exercise influence over both serotonin and dopamine receptors.
While neurotransmitter excess is one possible explanation for schizophrenia development, neurotransmitter deficiency can also cause schizophrenia-related problems. Specifically, researchers have explored a potential connection between schizophrenia and depleted levels of the neurotransmitter glutamate. This neurotransmitter serves as a foundation for learning and memory, so it is perhaps unsurprising that suppression of glutamate might cause disruption in normal thought processes. Some research even suggests that excessive dopamine receptors may lead to fewer glutamate receptors, which only fuels the damaging cycle of schizophrenic mental illness.