Twin Studies in relation to Scizophrenia

Description which includes strengths and weaknesses based on twin studies within schizophrenia research.

HideShow resource information
  • Created by: Issy H
  • Created on: 18-02-12 14:07
Preview of Twin Studies in relation to Scizophrenia

First 402 words of the document:

Twin Studies
Researchers focus on the study of
identical twins (MZ's) as they share
100% of their DNA, in order to
investigate the influence of genes and
see if there is a predisposition to
The findings from this are then
compared with twins who are less
genetically alike (DZ's), non identical
twins, which only share 50% of their
genes, but these twins would be likely
to share the same environment.
A concordance rate is given, which
states the rate of agreement between
the two variables (schizophrenic, or
Many other issues are investigated in
this method such as bulimia, IQ,
personality, depression and dyslexia.
In terms of Schizophrenia, we may look
at a pair of MZ twins who have been
separated (e.g. adopted) and if both the
twins develop schizophrenia, we can
assume that there is a genetic basis for
it. However, we may find the
concordance rate is only 70% not
Gottesmen argues for a genetic cause
of schizophrenia. He found that when
one MZ twin is schizophrenic, the other
one has a 50% chance of being
schizophrenic, or having other
disturbances. With DZ's however there
is only a 15% concordance rate. The
evidence is therefore quite strong that
schizophrenia has a large genetic
Strengths Weaknesses
Studies using twins help identify family There are problems with the design of
trends. Once the trends are identified, twin studies. For example a 50%
researchers can go on to carry out DNA concordance rate in schizophrenic DZ
tests to try and isolate the genes twins may mask other possible causes.
involved within schizophrenia. Twin studies are criticized for not
Findings from twin studies regarding the showing a cause and effect
genetic basis of behaviour provide relationship. E.g. a 50% concordance
controlled evidence for the nature rate suggests that schizophrenia runs in
debate. They demonstrate that much families. However, this doesn't mean
of our behaviour is inherited and not that the cause is nessercerily passed on
merely due to environmental through genes, as families share similar
influences. environments and experiences so
concordance may be to do with these
other factors.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

In many cases, it is difficult to find a
large sample of identical twins that
possess the variable we are looking for
(e.g. schizophrenia) and is even harder
to fins those who are reared apart.
It also operates on the assumption that
both twins have identical environments
as this may not be the case. E.g.
Rosenthal found a case of four identical
sisters in the 1930's. All developed
schizophrenia, but all had different
types, and it occurred at different times.…read more


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all resources »