OCD
Biological Explanations of OCD
The biological approach emphasises the importance of physical processes in the body such as
genetic inheritance and neural (brain) processes.
Genetic Explanations
The genetic explanation for mental disorders suggests that disorders are inherited, after all genes
are present in every cell in our body. This would mean that individuals inherit specific genes from
their parents that are related to the onset of OCD.
Gene: part of the chromosome of an organism that carries information in the form of DNA.
Lewis (1936) observed that out of his OCD patients, 37% had parents with OCD and 21% had
siblings with OCD.
Diathesis stress model:
A person can develop a mental health issue if they have a genetic vulnerability, as well as a life
experience that acts as trigger. This could be something like trauma, financial issues, death of a
loved one or loss of a job.
Candidate genes: Specific genes that have been identified by researchers which create a
vulnerability for developing OCD.
Examples:
The COMT gene: Regulates the production of dopamine (pleasure neurotransmitter).
The COMT gene is more common in those with OCD. The variation of this gene produces lower
activity levels of COMT, leading to higher levels of dopamine.
The SERT gene: Affects the transport of serotonin (mood regulating neurotransmitter).
A mutated variation of the SERT gene creates lower levels of serotonin, which are related to
OCD.
Ozaki et al (2003) found a mutation of the SERT gene in 2 unrelated families, where 6 out of the 7
family members had OCD.
Polygenic: There are several genes that cause something such as OCD.
, Taylor (2013) analysed the findings of previous studies and found that over 230 genes may be
involved with OCD.
Point Evidence Conclusion
A strength of the genetic Nestadt et al (2010) reviewed This therefore increases
explanation of OCD is previous twin studies and the credibility of genetic
that there is supporting found that 68% of identical explanations and suggests
research from twin twins (MZ) shared OCD as that the more shared
studies. opposed to only 31% of non- genetic material two
identical twins (DZ). individuals have, the more
likely they are both to
develop OCD, thus
suggesting there is a
genetic component to the
disorder.
A limitation of the If the genetic explanation was Therefore, the genetic
genetic explanation of a fully comprehensive explanation could be
OCD is that explanation of OCD, we considered reductionist,
environmental risk would expect to see a 100% as research suggests that
factors must also play a concordance rate in identical genes may provide a
role in the development twin studies, however we do genetic vulnerability to the
of OCD. not, suggesting there must be disorder but cannot
another contributing factor. provide a full explanation
Cromer et al (2007) found of OCD as concordance
that over half the OCD rates between MZ twins
patients in their sample had aren't 100%, suggesting
experienced a past other factors must play a
traumatic event and OCD role in the development of
was more severe in those that OCD.
had more trauma.
A strength of genetic Antidepressants that work Therefore, the genetic
explanations for OCD is purely on serotonin levels explanation for OCD has
that drug treatments are effective in reducing OCD value as it has expanded
that alter serotonin symptoms. our knowledge on the
levels are effective Particularly antidepressants effects of the mutated
treatments for OCD. that increase serotonin SERT gene and allowed us
activity have been shown to to create treatment for
those with OCD. This has a
Biological Explanations of OCD
The biological approach emphasises the importance of physical processes in the body such as
genetic inheritance and neural (brain) processes.
Genetic Explanations
The genetic explanation for mental disorders suggests that disorders are inherited, after all genes
are present in every cell in our body. This would mean that individuals inherit specific genes from
their parents that are related to the onset of OCD.
Gene: part of the chromosome of an organism that carries information in the form of DNA.
Lewis (1936) observed that out of his OCD patients, 37% had parents with OCD and 21% had
siblings with OCD.
Diathesis stress model:
A person can develop a mental health issue if they have a genetic vulnerability, as well as a life
experience that acts as trigger. This could be something like trauma, financial issues, death of a
loved one or loss of a job.
Candidate genes: Specific genes that have been identified by researchers which create a
vulnerability for developing OCD.
Examples:
The COMT gene: Regulates the production of dopamine (pleasure neurotransmitter).
The COMT gene is more common in those with OCD. The variation of this gene produces lower
activity levels of COMT, leading to higher levels of dopamine.
The SERT gene: Affects the transport of serotonin (mood regulating neurotransmitter).
A mutated variation of the SERT gene creates lower levels of serotonin, which are related to
OCD.
Ozaki et al (2003) found a mutation of the SERT gene in 2 unrelated families, where 6 out of the 7
family members had OCD.
Polygenic: There are several genes that cause something such as OCD.
, Taylor (2013) analysed the findings of previous studies and found that over 230 genes may be
involved with OCD.
Point Evidence Conclusion
A strength of the genetic Nestadt et al (2010) reviewed This therefore increases
explanation of OCD is previous twin studies and the credibility of genetic
that there is supporting found that 68% of identical explanations and suggests
research from twin twins (MZ) shared OCD as that the more shared
studies. opposed to only 31% of non- genetic material two
identical twins (DZ). individuals have, the more
likely they are both to
develop OCD, thus
suggesting there is a
genetic component to the
disorder.
A limitation of the If the genetic explanation was Therefore, the genetic
genetic explanation of a fully comprehensive explanation could be
OCD is that explanation of OCD, we considered reductionist,
environmental risk would expect to see a 100% as research suggests that
factors must also play a concordance rate in identical genes may provide a
role in the development twin studies, however we do genetic vulnerability to the
of OCD. not, suggesting there must be disorder but cannot
another contributing factor. provide a full explanation
Cromer et al (2007) found of OCD as concordance
that over half the OCD rates between MZ twins
patients in their sample had aren't 100%, suggesting
experienced a past other factors must play a
traumatic event and OCD role in the development of
was more severe in those that OCD.
had more trauma.
A strength of genetic Antidepressants that work Therefore, the genetic
explanations for OCD is purely on serotonin levels explanation for OCD has
that drug treatments are effective in reducing OCD value as it has expanded
that alter serotonin symptoms. our knowledge on the
levels are effective Particularly antidepressants effects of the mutated
treatments for OCD. that increase serotonin SERT gene and allowed us
activity have been shown to to create treatment for
those with OCD. This has a
