Causes Of Schizophrenia

Schizophrenia is a category of mental illness of the psychotic disorders. Psychosis refers to specific abnormalities of cognition that include delusions and hallucinations. The abnormalities of Schizophrenia are often divided into 3 categories. The first being cognitive which deals with abnormalities of attention and planning abilities. The second category of abnormalities of Schizophrenia is often called negative symptoms which can include blunted emotions and a loss of enjoyment. The third category is often called positive symptoms and this is what we refer to with the term psychosis because it can include things such as hallucinations or delusions. These are complex syndromes that span from different mental functions from the more thinking
type of functions which is cognitive, to the more emotional type of functions which would be negative symptoms, and to the more perceptual types of abnormalities which would be the positive symptoms.
As of now, the understanding of Schizophrenia and how it comes to be is very limited. What we know are things that may play some role in how the brain develops and how that leads to schizophrenia. In research, it has been seen for there to be quite the difference in brain appearance from people with and without schizophrenia. Some brain abnormalities of patients with schizophrenia can be seen even without a microscope. Just looking at the brain with the naked eye, you can see a difference. One difference is in the fluid filled structures inside the brain. In many patients with schizophrenia, those fluid filled structures tend to be larger than somebody who does not have the disorder. What people think this represents is that the actual amount
of brain tissue, when looking at the whole brain tissue itself, is reduced in size due to those fluid filled structures being a little larger than normal, and that causing the less total tissue of the brain. Going along with this idea is that the size of the cerebral cortex seems to have an overall decreased size and is somewhat thinner particularly in certain areas of the brain such as the frontal and temporal lobe. The part of the cerebral cortex that covers these lobes of the brain seem to have less tissue, and this is important because this region of the brain has a lot to do with cognitive and perceptual functions which are often abnormal in schizophrenia. If we take areas of the cerebral cortex and look at it under a microscope, there’s an organization of how the neurons and other brain cells layer with each other. In those people with schizophrenia, it has been seen that in these regions of the frontal and temporal lobes, the organization of the layers looks abnormal and disorganized. These are some of the physical differences that has been seen in people with schizophrenia compared to those that do not suffer from this disorder. A likely possibility for those that develop schizophrenia is that something happens abnormally during the development of the brain in these areas that is linked to the disease. Some features of schizophrenia also appear to have abnormalities in the neuronal pathway that uses dopamine as a neurotransmitter.
Dopamine is an important neurotransmitter in the nervous system that communicates a lot of information between neurons and parts of the brain. The networks of neurons that use dopamine appear to influence activity in different areas of the brain so that abnormalities can cause abnormal activities in certain parts of the brain. Importantly for schizophrenia, dopamine appears to play a big role in the activity in the frontal and temporal lobes of the brain. The regions that play essential roles in the cognitive, perceptual, and emotional functions that are often abnormal in schizophrenia. Supporting the idea that abnormalities of dopamine may be playing a role in schizophrenia, is the fact that a number of medications that effect dopamine transmission often improve many of the symptoms of schizophrenia. One pathway in particular has attracted a lot of attention and is most likely playing a role in schizophrenia. There are a collection of neurons right around the brain stem that use dopamine as their neurotransmitter so that their cell bodies are located in the ventral tegmental area. The cell body’s axons project to a number of areas throughout the brain to release that dopamine onto other neurons in many areas of the brain. This pathway is the mesocorticolimbic pathway. This pathway refers to where the neurons are starting, which is the mid brain
(meso). The cortical refers to the cerebral cortex, and many of these axons are projecting to areas of the frontal cortex, the cerebral cortex of the frontal lobe, and areas of the cerebral cortex in the temporal lobe. The limbic part of this term refers to a collection of structures that are inside of the brain that wrap around and involved with emotions, motivation, and a number of other brain functions. There does seem to be abnormal activity in this pathway that carries dopamine from the ventral tegmental area to these areas of cerebral cortex. So, abnormal activity in the mesocorticalimbic pathway leads to dysfunction in the parts of the frontal cortex that cause many of the cognitive symptoms of schizophrenia. Abnormal activity in parts of the limbic structures can cause many of the negative symptoms of schizophrenia, and abnormal activity in parts of the temporal cortex can cause many of the positive symptoms. Although this is a simple explanation, in reality the abnormalities involved appear to be far more complex. These are some patterns that have been seen in studies in people with schizophrenia, but doesn’t necessarily mean that this is the actual cause of this disorder. There are also clues of what may be causing these brain abnormalities in schizophrenia. Genetic studies show that schizophrenia can be inherited and that there are several genes related to the development of the brain and its function that has been associated with the risk of the disease. So when it comes to what causes schizophrenia, genes may play a role. Also, some other studies has suggested that some types of physical stress on the mother during pregnancy, such as infections, may increase the risk of schizophrenia especially during periods of pregnancy where the brain is being developed. Psychosocial factors may play a role as well because there might be a link between bad life experiences as a child can have an effect because the brain is still wiring itself and will not develop properly. All these may or may not be reasons to why somebody develops schizophrenia, but unfortunately all still hypothesis to this day.