What are the Causes of Schizophrenia – Genetic, Environmental or a Combination of Factors?


Ongoing research into the causes of schizophrenia is beginning to help scientists understand this disorder to a certain extent.

However, it is still not known for certain what causes schizophrenia.

It is known that the brains of people who have schizophrenia are different.
Particular genes seem to increase the risk, but they are not responsible for the illness by themselves.

Demystifying the Causes of Schizophrenia

Although there have been many myths associated with schizophrenia including that the person with this illness was possessed, this was due to a lack of understanding and fear.

Today, it is more widely perceived as what it really is – an illness.

Information on schizophrenia is more readily available and as with many things, this helps to debunk the myths and improve the general understanding of the illness.

Environmental Triggers

Some researchers believe that schizophrenia is not merely an inherited disease.
They believe the presence of environmental ‘triggers’ also contribute to the onset of schizophrenia.

What are these ‘triggers’?
They can include prenatal exposure to a virus when development of the brain is beginning – generally around the fifth month of pregnancy, complications that occur during pregnancy at the time of delivery or environmental factors such as puberty that are highly stressful times.

Other studies show childhood experiences, such as abuse is associated with the development of schizophrenia in adulthood.

There have even been studies that point to unfavorable social factors in childhood being linked to the possibilities of developing schizophrenia as an adult.

Brain Function

On the other hand, research also supports abnormal brain function as being one of the causes of schizophrenia.
When the part of the brain that is responsible for organization, planning and decision making – the frontal lobes – is not as active as it should be, this can be responsible for the negative symptoms of schizophrenia.

Parietal lobes are what regulate how the brain perceives stimuli that are associated with temperature, pressure and pain. Overactive parietal lobes are associated with the positive symptoms of schizophrenia.

There are also theories that support overproduction of neurotransmitters as a reason for schizophrenia.
The neurotransmitter, dopamine is one in particular.

This neurotransmitter is responsible for carrying signals between the brain’s nerve endings. They are in the ventral tegmental area (VTA) of the brain. These neurons are stimulated when good things happen and release dopamine.

One of the supportive aspects of this theory is the effectiveness of anti-psychotic medications for those with schizophrenia.
The medications block dopamine receptors and prevent them from making too much dopamine.

This allows relief from the symptoms of schizophrenia for many people.

The use of amphetamines, which are a drug of choice for many who abuse drugs, increase dopamine levels and can cause a schizophrenic paranoid state of mind.

As for the difference in the appearance of the brain for those with schizophrenia, scientists have found the ventricles or cavities filled with fluid at the center of the brain are sometimes larger in people with this disorder, which may be one of the causes of schizophrenia. They also found that their brains contained less gray matter.

Is Heredity one of the Causes of Schizophrenia?

Some studies on schizophrenia and bipolar disorder show that people who have family members with either of these conditions have a greater risk of developing the disorder.
The same studies show that people with a diagnosis of schizophrenia are at a greater risk for developing bipolar disorder.
Although schizophrenia and bipolar disorder have been considered two separate conditions, there are certain genes that appear to affect both.

According to these findings, some scientists believe that not only are both disorders hereditary, but they also share a common inherited cause.

Schizophrenia statistics show that this disorder occurs in approximately 1% of the population. The risk increases when a first-degree relative – a parent, sister or brother – has been diagnosed with schizophrenia. There is a higher risk for those with second-degree relatives – grandparents, aunts or uncles – as well.

Twins and Schizophrenia

When an identical twin is diagnosed with schizophrenia some researchers believe the risk for the other twin increases to a 40% to 65% chance, while the risk for a fraternal twin is about 15%.

While the consensus is that schizophrenia is an inherited disorder, another consideration is the “nature-nurture” argument.

Are the causes of schizophrenia mainly due to heredity or is the way that children of schizophrenics are raised a factor for developing the disorder?

When identical twins are raised in entirely different environments and are not aware of the presence of each other, if one develops schizophrenia, 50% of the time, so will the other twin.
The chances increase as they become older.

The same is not true for fraternal twins. Because only about half of the genes of fraternal twins are the same, their risk of developing schizophrenia is the same as other children who are not twins with the same parents.
This is part of the reason that genetic factors are considered so important to the science dealing with the study of this disorder.

Exposure to Certain Situations may be a Cause of Schizophrenia

When diagnosing schizophrenia, there is evidence that other than hereditary factors, certain situations can contribute to this disorder. The following may be causes:

• Consistent denial of problems in life

• Brain injury

• Delusions and hallucinations are symptoms linked to schizophrenia that can be experienced by people who have substance abuse problems

• Stress that is experienced long-term by those who are more at risk for developing schizophrenia can contribute to symptoms

One of the reasons that schizophrenia is difficult to diagnose is due to the variance in symptoms.
Early signs of schizophrenia are different for each person. The symptoms may come on suddenly or they may take months or even years to appear.

Although there are differing opinions on the causes of schizophrenia and many believe there is not a link between the psychological and genetic aspects, the fact remains that both aspects likely are responsible.

Research is still being conducted on many levels. At this time there is not a cure for schizophrenia, but early treatment can be conducive to the management of symptoms.

There are different schizophrenia types which affect everyone, women, men, teens and children. The effects of schizophrenia on adults and teens differ although some are similar.

Coping with schizophrenia involves several different types of treatment.

Most symptoms can currently be managed well with the right combination of treatment including therapy, medication and rehabilitation.

Continuing research into the causes of schizophrenia provides hope for an eventual cure and in the meantime, the quality of life can be greatly improved due to strides made in just the last few years.

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