Term Paper on "Schizophrenia Causation How Genetics, Brain Damage"

Term Paper 6 pages (1841 words) Sources: 6 Style: APA

[EXCERPT] . . . .

Schizophrenia Causation

How genetics, brain damage and environmental stresses interact to cause psychopathology.

Schizophrenia is one of the most severe chronic mental illnesses an individual can face over the course of his or her lifetime. People with schizophrenia can suffer a wide range of debilitating symptoms, including hearing voices that are not really there, feeling as if their thoughts are being controlled by outside forces, fearing that their minds can be read against their will, or they can exhibit other paranoid symptoms that alienate the individual from the rest of society. Schizophrenics often find it difficult to organize their thoughts and communicate with other people. Instead, they may speak with jumbled and disordered phrases (Spearing, 2002).

Schizophrenia is fairly rare. Approximately 1% of the population develops schizophrenia, or more than 2 million Americans a year. Schizophrenics are found all over the world. Although there is much modern research does not know about schizophrenia, what is known illustrates the complex interplay of genetics, environment, and physiology in the development of this mental disorder (Spearing, 2002). In an effort to shed some light upon the condition, geneticists are trying to trace the heritable factors that contribute to schizophrenia. "Several regions of the human genome are being investigated to identify genes that may confer susceptibility for schizophrenia. The strongest evidence to date leads to chromosomes 13 and 6 but remains unconfirmed" (Spearing, 2002). Most evidence suggests that several genes or combinations of genes contribute to a predisposition to develop schizophrenia. Prenatal difficulties like fetal starvation, maternal viral infections, birth complications, and a variety of fetal and maternal stressors, can also raise the individual's chance of developing schizophrenia later in life. But although a predisposition may be diagnosed, there is no way to conclusively predict whether a given person will or will not develop the disorder and manifest this tendency (Spearing, 2002). There is no way to demonstrate that the disorder will surface until the individual has begun to show symptoms. Psychologists and psychiatrists also must guard against mistaking the symptoms of schizophrenia for other disorders, like the manic stage of bipolar disorder.

Schizophrenic symptoms usually become obvious to others when an individual enters his or her first psychotic episode. There is often a clear dissociation from reality on the part of the patient. A state of psychosis may result in the individual suffering hallucinations, to experience strange sensory perceptions, or to brood over paranoid delusions. These symptoms may also precipitate alternations in personality and customary behavior. An individual may withdraw from society or use strange and phrases. A lack of appropriate emotion, or immobility to the point of catatonia, is witnessed in some sufferers. This withdrawal may arise because the individual is having difficulty dealing with his or her hallucinations or other symptoms, or as the result of paranoia. Children as young as five can exhibit symptoms of schizophrenia but these cases are rare (Spearing, 2002).

Schizophrenia affects men and women with equal frequency. However, the disorder often appears earlier in men, usually in the late teens or early twenties, than in women, who are generally affected in their twenties or early thirties (Spearing, 2001). The symptoms of schizophrenia may vary from person to person, yet research still demonstrates that schizophrenia, regardless of the specific symptoms of the individual, has a genetic causation. People who have a close relative with schizophrenia are much more likely to develop the disorder than are people who have no relatives with the illness. Twin studies, which researchers often use to examine the possibility of genetic causation of psychiatric disorders show: "a monozygotic (identical) twin of a person with schizophrenia has the highest risk - 40 to 50% - of developing the illness. A child whose parent has schizophrenia has about a 10% chance. By comparison, the risk of schizophrenia in the general population is about 1%" (Spearing, 2002). To name just one example, the younger, legitimate son of the famous recovered schizophrenic mathematician John Nash also developed schizophrenia (Nasar, 2001).

However, the illness is still relatively rare, and simply because someone comes from a family with a strong predisposition to develop schizophrenia does not automatically mean that he or she will be affected. "If, for example, you have an aunt or uncle who developed schizophrenia, then your risk (on average) is estimated at approximately 3% (and therefore there is a 97% probability you won't get schizophrenia). Even for the situation where one parent has schizophrenia the risk is estimated at 13% for a child who means there is an 87% probability that the person will not develop schizophrenia" (Corcoran et al., 2004). Such evidence supports the notion that no single gene or chromosomal abnormality seems to cause schizophrenia, unlike, for example, a genetic illness like hemophilia, which is clearly tied to a certain gene and can be traced fairly easily from generation to generation.

In addition to the genetic causation involved in schizophrenia, schizophrenia may also have a strong physical component. "Developmental neurobiologists funded by the National Institute of Mental Health (NIMH) have found that schizophrenia may be a developmental disorder resulting when neurons form inappropriate connections during fetal development. These errors may lie dormant until puberty, when changes in the brain that occur normally during this critical stage of maturation interact adversely with the faulty connections. This research has spurred efforts to identify prenatal factors that may have some bearing on the apparent developmental abnormality" (Sterling 2002). Such an explanation seems plausible, but does not answer why males, who enter puberty later, experience symptoms earlier than females, or why some prepubescent children suffer schizophrenia.

Birth trauma, malnutrition during infancy, and other physical factors increase the tendency of someone with a genetic predisposition to develop the disease. On brain scans, schizophrenia seems to leave a biological 'trace.' Many people with schizophrenia have enlargement of the fluid-filled cavities, called the ventricles, in the interior of the brain and decreased metabolic activity in certain brain regions. However, no specific brain abnormality has been found to present in all people with schizophrenia, nor do these characteristics occur only in individuals with this illness (Spearing 2002). "Microscopic studies of brain tissue after death have also shown small changes in distribution or number of brain cells in people with schizophrenia. It appears that many (but probably not all) of these changes are present before an individual becomes ill, and schizophrenia may be, in part, a disorder in development of the brain" (Spearing, 2002).

Does this mean that no amount of familial influence can counteract the risk? Not at all. In fact, "36.8% of high-genetic risk adoptees living in a dysfunctional family environment were found to have developed a schizophrenia-spectrum disorder, compared to only 5.8% of those in a healthy family environment. The rate of schizophrenia-spectrum disorders in the low-genetic risk adoptees was similar regardless of the family environment. This evidence suggests that people with high-genetic risk for schizophrenia-spectrum disorders receive a protective effect of the healthy family environment of 86% decrease in risk. The study suggests that children with genetic or biological liability for schizophrenia and related disorders may be sensitive to both difficult (volatile, unpredictable, judgmental or hostile) and overly protective or isolated environmental conditions" (Tienari, et al. 2004). In short, a bad environment cannot 'cause' schizophrenia automatically, anymore than a genetic predisposition to develop the disorder means that a doctor can predict, looking at the individual's genome, that a person will have schizophrenia.

Traumatic events often seem to precipitate the first psychotic episode in a young person's life. These stressors that might cause anyone anxiety, but seem to cause the genetic tendency to develop schizophrenia to surface. One of the reasons that the first exhibition of schizophrenia may manifest itself in most schizophrenic's teens or twenties may be because this period is often characterized by traumatic life changes, like going away to college, beginning a new job, or separating from home and family, as well as the hormonal effects of puberty. Research also suggests that living in an urban environment as a child, and being exposed to the stresses of urban life may increase the chance of developing the disorder. "Researchers have theorized that the increased schizophrenia risk may be due to increased transfer of infections (e.g. The flu) in higher density living situations, or higher levels of poverty, interpersonal stress, pollution, or noise in cities" (Information for Parents: How to Lower Your Child's Risk for Schizophrenia, 2004, Schizophrenia.com). Increased background noise while a mother is pregnant, not breast feeding, being exposed to cats, smoking, RH blood incompatibility, and a lack of omega-3 fatty acids are all traced to heightened risk, but it is uncertain if these factors are due to causation or merely correlate with the child being raised in a high-stress environment (Information for Parents: How to Lower Your Child's Risk for Schizophrenia, 2004, Schizophrenia.com).

But does this mean that the stresses of winter cause schizophrenia, or the type of care that women are likely to receive in the hospital at the time might make birth trauma more… READ MORE

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