THEORY & STUDY
Strengths - Biological Approach to Explaining OCD:
Genetic Explanations of OCD:
1. Family Studies:
1. The Role of Neurotransmitters:
1. Family Studies:
- Supporting Evidence: Indicates that close relatives of a person with OCD are more likely to have OCD themselves which suggests that genes are involved in causing OCD. The concordance rates in MIGUEL'S twin study are very high, suggesting that the genetic component is strong.
- Supporting Evidence: TAYLOR (2013) provides further support for the role of genes, finding that as many as 230 genes may be involved in causing OCD. This supports the idea that OCD is polygenic ie: caused by multiple, rather than single, genes.
1. The Role of Neurotransmitters:
- Supporting Evidence: Supports association between neurotransmitter activity and OCD. SZECHTMAN et al (1998) found that drugs which increase dopamine activity produce repetitive, stereotyped movements in animals, which resemble the compulsive behaviours observed in OCD patients.
- Neural explanations have led to promising drug treatments for OCD: if low serotonin and high dopamine levels cause OCD, drugs which correct this chemical imbalance may be effective treatments. PIGOTT et al (1990) found that drugs which increase serotonin activity decrease OCD symptoms. This both supports the role of neurotransmitters in OCD and provides evidence of useful, real life application of neural explanations.
- Supporting Evidence: SAXENA et al (1998) found that brain scans of patients with OCD support the suggestion that there are abnormally high levels of activity in the orbitofrontal cortex, caudate nucleus, thalamus and anterior cingulate gyrus. This shows that these brain structures play a role in OCD.
Limitations - Biological Approach to Explaining OCD:
Genetic Explanations of OCD:
1. Family Studies:
1. The Role of Neurotransmitters:
1. Family Studies:
- OCD is not solely caused by genes, as the concordance rate in identical twins is not 100%. The most likely explanation for this is diathesis-stress: genes can cause a biological vulnerability (diathesis), but other factors, such as life experiences, affect whether OCD actually develops.
- Family studies cannot rule out an environmental explanation for OCD running in families. It could be that OCD is learnt through observation or reinforcement EG: a child observed their parent compulsively washing, and the parent encourages the child to do the same. Therefore these studies may not provide strong support for a genetic basis to OCD.
- The sheer number of candidate genes reduces the usefulness of a genetic explanation of OCD, because it means that each gene has only a very small influence. Therefore it is unlikely that this research will be helpful in predicting who will be vulnerable to OCD, or in developing genetic treatments for OCD.
- A purely genetic explanation ignores the role of environmental risk factors, which may be more important, and more useful, to understand, than genetic influences.
1. The Role of Neurotransmitters:
- None of the supporting research demonstrates cause and effect. Both neurotransmitter imbalance and neural overactivity in certain brain structures may simply reflect the symptoms of OCD, rather than being a cause of those symptoms. EG: obsessive thinking may cause the biological change, not the reverse! Therefore, neural explanations can be criticised for merely describing what occurs in the brains of OCD sufferers, without adequately explaining why it occurs in the first place.
- Low levels of serotonin, and/or high levels of dopamine are found in other mental disorders too, such as depression and schizophrenia. It is therefore unlikely that these offer a specific explanation for OCD.
- There is evidence that biological explanations may not be necessary or appropriate, since psychological explanations, such as the two-process model, have also been found to explain OCD. therefore, genetic and neural factors may only offer an incomplete explanation of the cause of OCD.