Obsessive Compulsive Disorder (OCD)

Question 1

what are obsessions

Answer 1

recurrent or persistent thoughts that are unwanted and cause distress

Question 2

what are compulsions

Answer 2

repetitive activites that the persom feels driven to perform in response to an obsession

Question 3

give 3 behavioural characteristics of OCD

Answer 3

1. compulsions are repetive
2. compulsions reduce anxiety
3. avoidance

Question 4

give 3 emotional characteristics of OCD

Answer 4

1. anxiety and distress
2. accompanying depression
3. guilt and disgust

Question 5

explain 3 cognitive characteristics of OCD

Answer 5

1. obsessive thoughts - for 90% of people with OCD the main coginitive feature is obsessive thoughts
2. cognitive coping strategies - people adopt cogntitve coping strategies to deal with obsessions
3. insight into excessive anxiety - people with OCD are aware their obsessions are not rational

Question 6

genetic explanation

• explain the genetic explanation of OCD
• give studies which support this

Answer 6

Genes are involves in individual vulneranility to OCD

• Nestadt et al found 68% of monozygotic twins had OCD compared to 31% dizygotic twins
• Lewis observed that of his OCD patients, 37% had parents with the disorder

Question 7

genetic explanation

what is the diathesis stress model

Answer 7

where certain genes leave some people more likely to develop a mental disorder but is not certain

Question 8

genetic explanation

explain the study that is a weakness for the genetic explanation

Answer 8

Cromer et al (2017)

• found that over half of his OCD patients had experienced a traumatic event in their past
• this shows an environmental trigger is needed so dvelopment of OCD is not entirely genetic

Question 9

genetic explanation

give the 2 candidate genes which are involves in the development of OCD

Answer 9

• SERT
• COMT

Question 10

genetic explanation

explain how the SERT gene can lead to OCD

Answer 10

• this gene is responsible for the regulation of the serotonin system
• in people with OCD it is thought that this gene is faulty, leading to lower levels of serotonin
• this is thought to cause OCD symptoms

Question 11

genetic explanation

explain how the COMT gene can lead to OCD

Answer 11

• this gene is responsible for the production of an enzyme that breaks down dopamine
• it is thought that people with OCD have a mutation in this gene
• this causes higher levels of dopamine which are linked to OCD symptoms

Question 12

genetic explanation

a combination of genes deterine an individuals level of vulnerability to OCD, therefore OCD is ———-

Answer 12

polygenic

Question 13

neural explanation

explain the role of serotonin and how it may cause OCD

Answer 13

• serotonin is a neurotransmitter that regulates mood
• if someone has low levels of serotonin then they may experience low moods
• some cases of OCD may be explained by a reduction in the functioning of the serotonin system

Question 14

neural explanation

explain how the decision making systems may lead to OCD

Answer 14

• some cases of OCD may be associated with impaired decision making
• this may be associated with abnormal functioning of the lateral and orbital prefrontal cortex
• these lobes are responsible for logical thinking

Question 15

neural explanation

what brain areas are involved in the neural explanation of OCD

Answer 15

• caudate nucleus
• orbital frontal cortex

Question 16

neural exlanation

explain how the orbital frontal cortex and caudate nucleus can lead to the development of OCD

Answer 16

• PET scans show people with OCD have high levels of activity in the orbital frontal cortex, a brain area responsible for the initiation of acivity so sends a worry signal
• therefore, people with OCD send too much worry signals
• the caudate nucleus is responsible for suppressing some of the signals sent by the OFC but people with OCD have an impaired caudate nucleus
• this means the worry signals wont be switched off creating a “worry circuit”

Question 17

neural explanation

give a strength for the neural explanation of OCD

Answer 17

development of treatments such as SSRIs

Question 18

neural explanation

give a limitation for the neural explanation of OCD

Answer 18

all evidence is simply correlational

Question 19

neural explanation

what is the main treatment used for OCD

Answer 19

SSRIs

Question 20

neural explanation

explain how SSRIs work

Answer 20

• they prevent reabsorbtion of serotonin on the presynptic cell
• therefore, more sorotonin binds to receptors on the post synpatic cell

Question 21

neural explanation

give a strength of SSRIs

Answer 21

Soomro

• symptoms reduce by 70%

Question 22

neural explanation

give a limitation of SSRIs

Answer 22

side effects

Question 23

neural explanation

explain a treatment used for OCD other than SSRIs

Answer 23

benzodiazepines which slows down activity in the central nervous system by enhancing GABA activity

Question 24

How do low serotonin levels contribute to OCD’s “worry circuit”?

Answer 24

Serotonin usually dampens activity in the orbital-frontal cortex and caudate nucleus. When serotonin is low, this braking effect is lost, so the OFC keeps sending “worry” signals that the caudate fails to suppress. The overactive loop produces persistent obsessions and drives compulsive behaviours.