Obsessive-compulsive disorder (OCD)

Question 1

What is the cycle of OCD?

Answer 1

Obsessions -> anxiety -> compulsions -> relief ->

Question 2

What are obsessions?

Answer 2

Obsessions tend to be things people think about which lead to feelings of extreme anxiety

Question 3

What are compulsions?

Answer 3

Compulsions are what people do as a result of the obsessions

Question 4

What are the characteristics of OCD?

Answer 4

Behavioural:
- Compulsive behaviour
- Avoidance

Emotional:
- Anxiety and distress
- Accompanying depression

Cognitive:
- Obsessive thoughts
- Hyper vigalent

Question 5

What did Nedstadt et al find out about OCD?

Answer 5

Found lifetime prevalence of OCD was 11.7% in people who has first-degree relatives with OCD compared with 2.7% in the control group who has no first degree relatives with OCD

Question 6

What are monozygotic twins?

Answer 6

Identical twins

Question 7

What are dizygotic twins?

Answer 7

Non-identical twins

Question 8

What did Carey and Gottesman fin out about MZ twins?

Answer 8

MZ twins have a concordance rate of 87% for obsessive symptoms and features compared to 47% in DZ twins

Question 9

What is the COMT gene?

Answer 9

The COMT gene regulates the neurotransmitter dopamine, this results in higher levels of dopamine and this variation has been found to be more common in people with OCD

Question 10

What is the SERT gene?

Answer 10

Linked to serotonin and affects the transport of serotonin causing lower levels of serotonin which is also associated with OCD

Question 11

What does polygenic mean?

Answer 11

OCD seems to be polygenic meaning it is not only caused by one single gene but that several genes are involved

Question 12

What did Cromer et al find out about OCD sufferers?

Answer 12

Over half the OCD sufferers in their sample had a traumatic event in their pasts, this suggest that the diathesis-stress model would be a more suitable explanation for OCD.

Question 13

What did Pigott find out?

Answer 13

That anti-depressant drugs have been shown to reduce the symptoms of OCD

Question 14

What did Kim et al say?

Answer 14

Gave OCD sufferers drugs that affected their dopamine levels and found this was correlated with less compulsive behaviours

Question 15

Where is OCD most common in the brain?

Answer 15

There is increased activity in the orbitofrontal cortex and the caudate nucleus

Question 16

What did Saxena and Rauch find out?

Answer 16

Found out that after treatment activity in these brain areas reduces to a level comparable to that of controls (the orbital region)

Question 17

What are SSRI’s

Answer 17

A type of antidepressant drug which prevent the re-absorption and breakdown of serotonin. This results in more serotonin being available in the synapse.

Question 18

How do SSRI’s work?

Answer 18

• When serotonin is released from the neuron the bind to the receptors on the post-synaptic neuron
• Any not absorbed serotonin is absorbed into the post-synaptic neuron
• SSRi’s increase the level on serotonin available in the synapse while preventing it from being reabsorbed
• This results in most serotonin being received in the post-synaptic neuron

Question 19

What did Soomro et al say?

Answer 19

Reviewed 17 studies comparing SSRI’s to placebos in the treatment of OCD

SSRI’s were more effective than placebos especially between 6-13 weeks, this suggest that drug therapies are only short-term treatments for OCD

Question 20

What did Cromer et al say?

Answer 20

Suggests that some causes of OCD are linked to trauma therefore SSRI’s can only help in the short-term so CBT might be a good treatment so people dont relapse