Studied by 6 people
What does the Biological Model assume about psychological disorders are physical illnesses?
It assumes that psychological illnesses have physical causes. In principle, they’re no different from physical illnesses like the flu, except they have major psychological symptoms
What are Genetic Factors?
Some researchers think that genetics plays a part in OCD. Studies have looked at OCD rates among people with a relative who has OCD, to see if having a relative with OCD significantly increases your chances of developing it
Who gave evidence for genetic factors?
Billet et al (1998) did a meta-analysis of twin studies that had been carried out over a long period of time. They found that for identical twins, if one twin had OCD then 68% of the time both twins had it, compared to 31% for non-identical twins
Pauls et al (2005) found that 10% of people with an immediate relative (i.e. parents, offspring or siblings) also suffered from the disorder. This is compared to around 2% of people in the general population
What gave evidence against genetic factors?
No study has found a 100% concordance rate, so genetics can’t be the full story of OCD. Children may imitate the obsessive and compulsive behaviour of their relatives
Concordance rates don’t prove that OCD itself has other contributing factors
Biochemical Factors
PET scans have shown that levels of the neurotransmitter serotonin are lower in OCD sufferers
Involves lower serotonin levels in OCD sufferers, with SSRIs showing symptom reduction in 50-60% of cases.
Who gave evidence for biochemical factors
Insel (1991) found that a class of drugs called SSRIs, which increase levels of serotonin, can reduce symptoms of OCD in 50 to 60% of cases.
Zohar et al (1996) also found that SSRIs alleviated symptoms in 60% of patients with OCD
What gave evidence against biochemical factors
SSRIs appear to offer some relief to sufferers of OCD. However, as this is not true in 100% of cases, there must be more to understanding OCD
The link with serotonin is correlational, so it doesn’t show cause and effect. It may be that decreased serotonin levels are a symptom of OCD, rather than a cause of it
Neurological Factors
Abnormalities in the basal ganglia may be linked to OCD, supported by increased OCD rates in those with basal ganglia damage.
Who gave evidence for neurological factors
Max et al (1995) found increased rates of OCD in people after head injuries that caused brain damage to the basal ganglia
Other researchers have found increased activity in this area during OCD-related thoughts and behaviours
OCD is often found in people with other diseases which involve the basal ganglia, e.g. Parkinson’s and Huntington’s disease
Who gave evidence against neurological factors
Aylward et al (1996) didn’t find a significant difference in basal ganglia impairment between OCD patients and controls
Basal ganglia damage hasn’t been found in 100% of people with OCD, so it can’t be the full story
What are the strengths of Biological Explanation?
Supported by scientific evidence like low serotonin levels and basal ganglia damage correlating with OCD, and twin studies showing genetic influence.
What are the weaknesses of Biological Explanation?
Fails to consider environmental, familial, and social factors, and biological therapies like SSRIs may only suppress symptoms and raise ethical concerns.
Biological Therapy for OCD
Involves drug therapy using SSRIs to increase serotonin levels, which have shown effectiveness in reducing obsessional thoughts but may have side effects and relapse rates.
Advantages of OCD being treated using biological therapy
Several researchers have found SSRIs to be effective in treating OCD. Thoren et al (1980) found that the use of an SSRI was significantly better at reducing obsessional thoughts than a placebo
Research has found that using other antidepressants that don’t affect serotonin levels is ineffective at reducing OCD symptoms
Disadvantages of OCD being treated using biological therapy
Up to 50% of patients with OCD don’t experience any improvement in their symptoms when taking SSRIs. Out of those that do improve, up to 90% have a relapse when they stop taking them
SSRIs have to be taken for several weeks before the patient experiences an improvement in their symptoms
Side effects of using these types of drugs include nausea and headaches, and sometimes increased levels of anxiety. This can cause people to stop taking their medication
