Download Biological explanation of OCD

Biological explanation of OCD
Genetic explanation
 It has been proposed that there is a genetic component to OCD which means some individuals might be more likely
to get it according to their family history of anxiety disorders
 McKeon and Murray (1987) found that patients with OCD are more likely to have an immediate (‘_______
____________’) relative with an anxiety disorder suggesting a genetic link
 Pauls et al (1995) found a much higher percentage of OCD sufferers (_____%) in relatives of patients with OCD than
in a control group without OCD (_____%)
_____________ explanation
 OCD only responds to those drugs that affect serotonin; this suggests that OCD is related to low levels of the
neurotransmitter serotonin in the brain.
 Drugs which increase the amount of serotonin known as ‘SSRIs’ reduce OCD symptoms, therefore providing support
for the theory that low levels of serotonin may be responsible for OCD.
Neurophysiological explanation
 Neuroimaging techniques (e.g. PET scans) have shown that a part of the brain known as the ___________
_______________ may have a part to play in OCD.
 Rapoport and Wise (1988) suggested that hypersensitivity of the basal ganglia gives rise to repetitive motor
behaviours such as those found in OCD patients, e.g. repetitive handwashing.
Evaluation of biological explanations of OCD
(-) (genetic exp) findings from family studies used to support the genetic explanation could be explained by environmental
influences, e.g. observing and imitating behaviour shown by relatives (________)
(-) (biochem exp) Studies on SSRIs which increase levels of serotonin only report a ______% improvement in symptoms
suggesting that there are other explanations of OCD
(-) (biochem exp) There is a time delay before any improvement in OCD is noticed; taking SSRI medication doesn’t improve
symptoms for __________ weeks
(-) (neurophys) evidence for structural abnormality in the basal ganglia is inconsistent. Aylward et al (1996) found no
significant differences in the basal ganglia structures of OCD patients and controls.
Biological treatment of OCD

SSRIs are a group of anti-depressant medications which are the most widely prescribed drugs for anxiety disorders.

SSRIs increase the levels of the neurotransmitter serotonin in the brain by preventing the ____________ of serotonin
at synapses (spaces between nerve cells). Because depression frequently accompanies OCD, SSRIs are particularly
beneficial for this anxiety disorder.

MAOIs are an older type of anti-depressant which are sometimes used for those who gain no benefit from SSRIs
Evaluation of biological treatments of OCD
(+)SSRIs are easily tolerated and are safe, even for older patients. They are not ____________ and can be used in the longterm.
(+) Drug treatment is quicker and cheaper than psychological therapies
(-) SSRIs cause side effects (headaches, nausea, sexual dysfunction), there can be relapse when coming off the medication
(-) SSRIs take _________ weeks before any therapeutic effect is noticed, this, together with side effects, can cause people to
stop taking the medication which can lead to relapse
(-) MAOIs are effective but they are last in line to be used for treatment due to side effects e.g. weight gain, sexual
dysfunction.
(-) A serious rise in blood pressure can occur when MAOIs are combined with foods containing the amino acid tyramine
found in certain foods e.g. _________, ____________.