There are many answers to questions inquiring into the root causes of schizophrenia, and while these answers are somewhat satisfactory, the entire truth of the matter is that the picture is not clear. Place several medical professionals in one room and ask this question and be ready for a debate that will last for ages. The reason is that for all of the proposed mechanisms of schizophrenia, some professionals discount, disagree to the level of each mechanism’s contribution, or solely propose that a single factor is to blame.
The Confusion of Causality – What Causes Schizophrenia?
Another item of interest that increases the level of confusion in determining the cause of schizophrenia has to do with the fact that there is no specific common factor amongst all people diagnosed. This has led many researchers to adopt the belief that schizophrenia may be the result of certain vulnerabilities of the brain and psyche in combination with exposure to certain stressors in life.
With this being said, we will take a look at each possible contributing factor to the schizophrenic syndrome, hopefully to shed some light on the possible interactions between them. We will concern ourselves with genetics, prenatal and perinatal causes, brain infections, childhood exposures and environmental causes, substance abuse, and life stressors.
The Contribution of Genetics
After much research, it has been concluded that there are many genes that all interact in tandem to create a vulnerability in a person which could result in a schizophrenia diagnosis.
For example, reelin is a glycoprotein that regulates and enables the process of neural migration in the hippocampus in the brain. More than half of schizophrenics in a particular study had genetic issues that related to a lessoning of the expression of reelin compared to the control group of non-schizophrenics. These reelin deficits also exist in people diagnosed with autism and manic-depression as well. This is simply a correlation and not true causation, because it is difficult to isolate the variable of anti-psychotic medications which also affect the levels and expression of reelin. It would be unethical to deny someone the medications that make them more comfortable. Time will tell on this one.
In meta-analyses of many studies using twins, it was determined that the risk for being diagnosed with schizophrenia was up to 75% if a parent was diagnosed. This means that some vulnerability is definitely inheritable. Monozygotic twins featured a concordance rate of almost 50%, while dizygotic twins were lower, but still significant, at 18%. Even longitudinal adoption studies show that there is an increased risk is children of a schizophrenic parent when raised apart from the parent.
Of course, there are arguments concerning the methodology of the studies, or the consideration of the placenta as part of the environment, all which blur the contribution of genetics as a cause for schizophrenia. If you were to locate and read the many other genetic studies, besides just the small sampling mentioned above, you would likely conclude with some confidence that genetics does play a role in a diagnosis for schizophrenia. The questions remains, “how much of a role?”
Prenatal and Perinatal Causes
Complications in the womb or at the time of birth are without question a contributor to an eventual diagnosis, although the risk they add is small in relation to other factors. Obstetric problems arise in the birth process of at least one fourth of the population, and most of these individuals do not become schizophrenic, and also many people diagnosed with schizophrenia never had any negative events prenatally. It is not known what it is in these negative obstetric events that contributes to schizophrenia, which is why it is considered a non-specific risk factor.
There have been some non-scientific correlations drawn that suggest various mechanisms through which a prenatal event can increase the risk. For instance, babies born in the spring or winter months in the northern hemisphere have an increased, although admittedly small, chance of an eventual diagnosis. Many attempts to connect the dots have been made, from an increased exposure to viruses or a lack of exposure to vitamin D during these months. Another correlation drawn was the increased amount of diagnoses made for children whose mothers were pregnant during the 1944 famine in the Netherlands. This means there could be some connection between malnutrition and hunger and schizophrenia. Stressors on the mother, such as cases where the husband perished during war time, seems to increase the probability of a diagnosis as well.
Attempts to find correlations between low birth weights and schizophrenia have been made but are not conclusive in any fashion. A contributor to low birth weight is, however, low oxygen levels, known as hypoxia, and is a definite risk factor for schizophrenia. Between hypoxia and issues surrounding metabolism, clinicians have been able to identify the schizophrenic nine times out of ten. They both influence the possibility of developing schizophrenia. Part of the reason hypoxia contributes to susceptibility is that a reduced level of oxygen in the fetus is related to a reduced volume and mass in the hippocampus, which as we discussed earlier with reelin can have a significant impact on the development of schizophrenic symptoms. Of course, exposure to toxic elements such as lead while in the womb can enhance the risk as well.
Viral Infections and Exposure
In early childhood, including toddlerhood or even in utero, being exposed to certain, yet plentiful, viruses can increase the risk of a schizophrenia diagnosis. As mentioned earlier, being born in the spring or winter when viral infections are more prevalent can result a higher chance of developing this psychological disorder.
There have been a couple studies that have demonstrated, and a couple that haven’t found, a correlation between exposure to influenza as a child and the emergence of schizophrenia later in life. There are other viral infections that have been found to increase the likelihood of this mental illness emerging, such as herpes, rubella, measles, polio, and others.
In relation to viruses, there have been studies that seem to link autoimmune deficiencies and diseases with schizophrenia. Support for this pathogenic or germ theory of schizophrenia lies in the presence of certain antibodies in the body, meaning the individual has either been exposed to a certain virus in the womb or to the antibodies to the virus after the mother had become infected and began warding off the virus.
Other exposures during the early stages of life can leave visible behavioral signs that can be indicative of the future possibility of schizophrenia. Large indicators are deficits in motor skills and other neurobehavioral problems. Consistently reaching normal developmental milestones late, such as the appearance of proper speech, socialization, emotional expression, school performance, and other somewhat general items can all be indicative of a higher risk of developing this illness. In regards to the environment, physical, psychological, and emotional abuse or trauma experiences also elevate the risk of schizophrenia development.
Substance Abuse and Chemical Dependency
Drug use has a strange relationship with our psychological impairment of concern. It does seem that there are instances of drug-induced schizophrenia in individuals who may have seemed to carry a predisposition for the illness. They can also trigger a relapse, which is why anyone with schizophrenic symptoms should certainly abstain altogether from substance use.
The difficulty in comprehending the relationship is that, some of the symptoms arising in schizophrenia can also arise from drug use. And we can’t know whether the chemical dependency began after the symptoms of schizophrenia appeared and were used as a method of self-medicating, or whether the substance abuse began before and triggered the schizophrenic break.
High levels of cannabis consumption have been attributed with doubling and even up to multiplying the risk of developing schizophrenia by six times. It is said to be responsible for just under ten percent of cases of schizophrenia altogether. Amphetamines can not only mimic but worsen the symptoms of schizophrenia due to the excessive release of dopamine. Hallucinogens produce states that closely resemble schizophrenic states, especially the dissociatives. These all have the potential to trigger and emergence of symptoms.
Life Stressors and Experiences
The more negative factors in childhood, such as low socioeconomic status or being ostracized can greatly increase the chances of developing this psychological difficulty. Dysfunction within the family, being discriminated against for races, gender, or sexual preference, unemployment, and more are all risk factors.
Hostility, authoritarian personality styles that are commandeering and controlling, intrusions, and other negative relationship styles that are present during critical moments can trigger the emergence or a relapse of schizophrenic symptoms. A low sense of self, self-imagery, self-perception and confidence, and other self-disapprovals all increase the risk.
Concluding the Causes of Schizophrenia
Although the above represent many of the possible factors influencing the risk of developing schizophrenia, there are some notable psychiatrists and psychologists who feel that the symptoms are not simply meaningless expressions of an illness, but are cathartic expressions indicative of a transformative experience.
They believe that schizophrenia and madness arise as a response to the demands that cannot possibly be filled by the individual. Society and family can have expectations that are incomprehensible, contradictory, or impossible, and when placed on sensitive individuals, the mind begins to attempt to reconcile these things and spews forth psychotic material, that if interpreted in the context of the individual’s situation, can offer insight into the situation and a possible cure.
Whatever the true causes are, we are coming ever closer to learning. We, as a society, will never cease the hunt until the cause is determined, and a method for prevention and/or cure is available!