Causes of schizophrenia
Causes of schizophreniaCauses of schizophrenia, bipolar disorder
and related illnesses
Illnesses like schizophrenia bring untold misery to sufferers and
their families. The suffering is magnified because of the unique
stigma attached to these illnesses. Unlike other illnesses, it marks
not only afflicted individuals, but also their relatives. For example the concept of the "schizophrenogenic mother" was rife till
recently. Such suffering is unnecessary and probably arises from
fear bred by ignorance. Our primary aim - search for the causes of
psychotic illnesses like schizophrenia - may help dispel these notions.
Our research is hampered by the relatively few clues available about the causes. This is not for lack of effort. Literally hundreds of causes have been proposed. They include viruses, accidental injury before and after birth, as well as illicit substances. However, only inherited factors are generally accepted as significant causes. Evidence for such factors comes from every day experience: it is common to find families with several affected members. While such clustering'could also be due to shared non-inherited (environmental') factors,more convincing evidence has come from twin studies, as well as studies of ill individuals who were adopted away before the onset
of illness.
It is fair to say that even such studies do not suggest inherited
factors as the sole causes. A more reasonable explanation is that
there are individuals who have an inherited proneness to illness.
Such individuals may fall ill, if in addition, they are exposed to
noxious factors in the environment such as drugs. This model' is
similar to that already proven in the causation of diseases like
diabetes and raised blood pressure. It is important to stress that
statistical analysis does not support the presence of a single genetic
factor in this scheme. Rather, the inheritance is probably due to
several factors which may be inherited from either side of one's
family.
We have based our research on this model. We assume that a
single genetic factor is unlikely to cause psychotic illnesses like
schizophrenia. Therefore, we do not trace the inheritance of
genetic factors in families, as is done in classical genetic studies.
Instead, we attempt to identify genetic factors which are present at
higher rates among ill individuals compared with ill individuals. If
such factors are identified, they may give us clues about the
location of genes which alter the susceptibility to illness. We
initially compared ill individuals with unrelated unaffected
individuals. Though we identified some differences in this manner,
it was difficult to say if the differences reflected proneness to illness or some other unrelated characteristics which happened to be
different in the two groups. To overcome these difficulties, we are
now conducting such comparisons among ill individuals and a
hypothetical' group. This group is made up of genetic factors not
inherited by a given ill person from his or her parents. Families with
one or more ill members...
To view the complete essay, you be registered.