the biological approach

The biological (biogenic) approach assumes
that many forms of psychopathology are caused by abnormalities of the
body, usually the brain. These abnormalities can be inherited or can occur
for other reasons. What these “other reasons” are is unclear, but they may include
birth complications, environmental toxins, or illness of the mother
during pregnancy.
Schizophrenia is one disorder that receives much attention among those
researchers who follow the biogenic approach. A great deal of research has
been conducted on the importance of neurotransmitters. Nerve cells in the
brain are not connected; there is a small space between them. A nerve impulse
travels this space by the release of chemicals in one nerve cell, called
neurotransmitters, which carry the impulse to the receptors of the next cell.
There are a large number of neurotransmitters, and new ones are discovered
periodically. Early research on the relationship between neurotransmitters
and psychopathology tended to view the problem as “too much” or “too little” of the amount of neurotransmitters. It is now known that the situation
is much more complicated. In schizophrenia, the neurotransmitter
dopamine has received most of the attention, with many studies suggesting
that excessive amounts of dopamine cause some of the symptoms of schizophrenia.
In fact, drugs that reduce the availability of dopamine to the cells
are successful in alleviating some symptoms of the disorder. However, not all
people with schizophrenia are helped by these drugs, and some people are
helped by drugs that one would not prescribe if the sole cause of schizophrenia
is too much dopamine. Researchers are finding that the way in which dopamine
and another neurotransmitter, serotonin, work together may lead
to a better biological theory of schizophrenia than the excessive dopamine
hypothesis.
The biological approach is a highly technical field, and it relies heavily on
advances in technologies for studying the brain. Powerful new tools for
studying the brain are invented at a rapid pace. For example, researchers
are now able to use neuroimaging techniques to watch how the brain responds
and changes from second to second.
Heredity appears to be important in understanding who develops what
kind of psychological disorder, but it is often unknown exactly what is inherited
that causes the disorder. The fact that schizophrenia runs in families
does not reveal what is being passed on from generation to generation. The
fact that inheritance works at the level of gene transmission places hereditary
research squarely within the biological approach.
One method for addressing the question of whether a disorder can be inherited
is by studying twins. Some twins are identical; each twin has the same
genes as the other. Other twins share only half of their genes; these are fraternal
twins. If one identical twin has schizophrenia and the disorder is entirely
inherited, the other twin should also develop schizophrenia. Among
identical twins, if one twin is schizophrenic, the other twin has a 48 percent
chance of having the same disorder, not a 100 percent chance. For fraternal
twins, if one is schizophrenic, there is a 17 percent chance that the other
twin will have the disorder. If neither twin has schizophrenia, and no one
else in the immediate family has the disorder, there is only a 1 percent
chance of developing this form of psychopathology.
Two important points can be made. First, genes matter in the transmission
of schizophrenia. Second, the disorder is not entirely due to heredity.
Researchers who focus on heredity have found that some other disorders
seem to have a genetic component, but no mental illness has been found to
be entirely due to heredity. Clearly, there are other factors operating, and
the biological approach must be integrated with other approaches to gain a
full picture of the etiology of psychopathology. 678