eval

• AO3


  Assessment Objective 3
• Higher concordance rate found for identical twins

  May be due to nurture, as identical twins are likely to experience a more similar environment than fraternal twins since they tend to be treated the same
• Genes alone do not determine who will develop OCD—they only create vulnerability
• OCD is due to an interaction of genetic and other factors
• OCD may be culturally rather than genetically transmitted


  As the family members may observe and imitate each other's behavior, as predicted by social learning theory
• Family members might be more vulnerable to OCD

  Because of the stressful environment rather than genetic factors
• AO3

  The brains of OCD patients are structured and function differently from those of other people. Brain scans of OCD patients reliably show increased activity in the PFC (Salloway & Duffy, 2002).
• Low serotonin


  Related to OCD
• It is unknown whether low serotonin causes OCD
• It is difficult to establish whether the low levels of neurotransmitters cause OCD, are an effect of having the disorder, or are merely associated
• Causation cannot be inferred as only associations (i.e., correlations) have been identified
• We do not know whether high levels of dopamine cause OCD or whether OCD is caused by something else and the effect is high levels of dopamine
• The biochemistry hypothesis does not account for individual differences because the research does not explain why one individual develops OCD and another develops a different mental disorder because low serotonin levels are also found in other mental disorders
• Biochemical abnormalities are not specific to OCD and may be true of mental distress
• Psychological therapy (CBT) can be a very successful treatment, and this is difficult to account for in the serotonin hypothesis
• Drugs show only partial alleviation of the symptoms, so the process is not fully understood
• The exact function of neurotransmitters in the development of OCD is far from understood
• Side effects of most SSRIs

  • Dry mouth
  • Slight tremor
  • Fast heartbeat
  • Constipation
  • Sleepiness
  • Weight gain
• The success of antidepressant drugs as a treatment

  Does not necessarily mean the biochemicals are the cause of OCD in the first place
• Treatment etiology fallacy


  Using headaches as an example, aspirin works well as a treatment, but this doesn't mean the headache was due to an absence of aspirin
• But research results relating to serotonin are varied – sometimes symptoms have been made worse. There is a great deal of contradictory research.
• AO3

  Studies using drugs have shown a reduction in dopamine levels is positively correlated with a reduction in OCD symptoms.

  Experiments that inject animals with drugs that increase levels of dopamine have caused the animals to demonstrate OCD-type behaviors.

  Drugs that increase serotonin (antidepressants such as SSRIs) have been shown to reduce OCD symptoms. Soomro et al. found that SSRIs were significantly better than placebos in reducing symptoms in 17 different clinical trials