The biological approach to explaining OCD

Question 1

A01 genetics

Answer 1

• Different, specific genes are inherited which are related to the onset of OCD
• COMT gene- involved in production of catechol-O-methyltransferase( COMT), which regulates the production of neurotransmitter dopamine that is implicated in OCD ( induces stereotyped movement resembling compulsive behaviours found in OCD patients)
  A specific allele which produces lower activity of the COMT gene and higher D levels is found more in ocd patients than non ocd patients
• SERT gene affects transport of serotonin creating lower levels, implicated in ocd
• Each of these genes create a diathesis for ocd and other disorders, other stressors affect what condition develops, these genes arent the sole factor for ocd

Question 2

AO1- neural explanations OCD brain circuits

Answer 2

• Several areas in the frontal lobes of the brain are thought to be abnormal in those with OCD
• The caudate nucleus normally suppreseses signals from the orbifrontal cortex. In turn the OFC sends signals to the thalamus about worrying things such as germ hazards
  When the caudate nucleus is damaged, it fails to suppress minor worry signals so the thalamus is alerted in turn sending signals back to the OFC acting as a worry circuit

Question 3

AO1 neural neurotransmitters

Answer 3

Genetic factors may affect certain brain circuits and levels of neurotransmitters that are abnormal
- Dopamine levels are high in people with ocd, based on animal studies- high doses of drugs that enhance the amount of dopamine induce stereotyped movements resembling compulsive behaviours found in ocd patients ( szechtman 1998)
- Serotonin low levels are associated with ocd, based on the fact that antidepressant drugs which inc serotonin levels are shown to reduce ocd symptoms, however drugs which dont effect serotonin levels dont ease symptoms of ocd ( jenicke 1992)
Abnormal brain circuits-
Caudate nucleus which usually supresess signals from OFC, can damage causing minor worries to not be supressed causing thalamus to alert , which in turn sends signals back to the OFC causing a worry circuit

Question 4

Evidence- study of genetic basis of OCD

Answer 4

• Nestadt et al ( 2000)
• Got 80 patients with OCD and 343 of their first degree relatives to compare with 73 control group patients and 300 of their relatives
• Found that people with a first degree relative with OCD had a 5 times greater risk of having OCD at a point in their lives compared with general population
  A meta analysis of 14 twin studies proved that monozygotic twins were more than twice as likely to develop OCD if their other twin had it than dizygotic twins ( billett et al)
  This is a strength of the biological explanation as the explanation claims that there is a
  genetic basis and vulnerability e.g., COMT and SERT that leads to the onset of OCD. This is a strength as evidence from first-degree relatives and twin studies supports this as if an
  individual has a direct relation with OCD, then they themselves will have a heightened genetic
  vulnerability to developing the condition

Question 5

Weakness- alternative explanation for biological explanation

Answer 5

Psychological explanations can also explain OCD
The 2 process model suggests that initial learning occurs when a NS ( dirt) is associated with anxiety.
Maintained through positive/ negative reinforcement.. ( explain that e.g avoiding a negative stimulus)]
This means obsession is formed, such explanations have successful results when this is considered e.g exposure response therapy, gold standard treatment.
Refraining from compulsive behaviour whilst facing fears
L- weakness , explain biological e.g caused by allele of comt and sert uggesting that the biological explanation is a reductionist theory of OCD as it reduces the onset of OCD to our genetics alone. Thus, the theory may oversimplify the causes of OCD and may lack validity.

Question 6

Weakness AO3 uses animal studies

Answer 6

Sztechman et al 1998, provided evidence for the role of neurotransmitters such as dopamine through animal research. Claims that when animals dopamine levels were enhanced it led to stereotypical induced movements liek that of patients with OCD
L-This is a weakness of the biological explanation as although humans and animals share most genes, the human mind and brain are much more complex. Therefore, this suggests that the explanation has low generalisability and external validity as it may not be possible to generalise from animal repetitive behaviour to human OCD. Thus, challenging the accuracy of the neural explanation of depression giving it low validity.