Zusammenfassung der Ressource
5.6 The Biological Approach to explaining OCD
- Genetic Explanations
- Aubrey Lewis (1936)
- 37% had parents with OCD
- 21% had siblings with OCD
- Suggests that OCD runs in families
although what is passed down could
be more commonly known as
genetic vulnerability.
- Candidate Genes
- Genes which have been
implicated in the development
of OCD.
- E.G The SERT gene which is involved
with regulating serotonin
- E.G The COMT gene, regulating the
function of dopamine.
- OCD is polygenic
- Caused by the
development of as many
as 230 genes
- Different types of OCD
- One group of genes may cause
OCD in one person but a
different group may cause the
disorder in another person.
- Evaluation
- Strengths
- Research support.
- Nestadt et al (2010) reviewed twin studies.
Found that 68% of identical twins shared
OCD but only 31% of non identical.
- Marini and Stebnicki (2012) Family studies. Found that
when one family member is diagnosed with OCD, the rest
are 4 times as likely to be diagnosed.
- Weaknesses
- Environmental Factors
- Individuals may gain vulnerability to OCD
through an environmental stressor.
- Cromer (2007) found that over half of the
OCD patients in the sample developed
OCD after a traumatic event in the past.
- Too many genes involved to
pinpoint specific ones.
- Neural Explanations
- Abnormal levels of certain
neurotransmitters
- If a person has low levels of serotonin then normal
transmission of mood-relevant information does not
take place and a person may experience low moods.
- Certain brain circuits may be
faulty
- Basal Ganglia
- Hypersensitivity of basal ganglia
results in a rise of repetitive motor
behaviours.
- Orbitofrontal Cortex and Thalamus
- Involved with decision making. An overactive
thalamus would result in increased motivation to
clean or check for safety. An overactive OFC means increased anxiety.
- Evaluation
- Strengths
- Antidepressants which work purely on
serotonin help in reducing OCD symptoms
suggesting serotonin is involved in the process
of OCD.
- Brains of OCD patients are
structured differently which can
be seen in brain scans.
- Weaknesses
- Cant distinguish whether low
dopamine is a factor in OCD or just an
effect of OCD.