🟠 Psychopathology - OCD Flashcards
What is OCD
an anxiety disorder, characterised by irrational, persistent and intrusive thoughts (obsessions) and intense, uncontrollable urges to complete tasks (compulsions)
Behavioural characteristics of OCD
- COMPULSIONS, they are repetitive (compelled to repeat a behaviour) and they reduce anxiety by performing these obsessions
- AVOIDANCE, sufferers may try to reduce anxiety by staying away from situations. For example, the sufferer may have irrational thoughts about germs in a bin so they don’t go near it
Emotional characteristics of OCD
- ANXIETY AND DISTRESS, caused by powerful axiety DEPRESSION obsessions and compulsions
- DEPRESSION, due to discomfort and interference
- GUILT AND DISGUST, directed internally or externally at the world
Cognitive characteristics of OCD
- OBSESSIVE THOUGHTS: 90% of OCD sufferers main cognitive features recur over and over
- COGNITIVE STRATEGIES: sufferers can respond to obsessive thoughts by using cognitive coping stragetiesm
- INSIGHT TO EXCESSIVE ANXIETY: sufferers are aware that their obsessions and compulsions are irrational
OCD CYCLE
obsessive thoughts
Anxiety
Compulsive behaviour
Temporary relief
Concordance rate
Measure of genetic similarity
Dompamine
A key neurotransmitter in the brain which effects motivation and drive
Serotonin
Another neurotranmitter which is believed to have an effect on mood regulation
Diathesis stress model
psychological theory that explains mental disorders as a result of a combination of environmental stressors and a person’s inherent vulnerability
What is the COMT gene
The gene is associated with the production of an enzyme that regulates the function of dopamine
What does the variation of the COMT gene do
Decreases the amount of COMT available and so dopamine is not controlled and there is probably too much dopamine (associated with OCD)
Why does too much dopamine cause OCD
Because it potentially disrupts the brains reward system leading to an increased focus on repetitive behaviors (compulsions) that are aimed at achieving a sense of relief from anxiety caused by intrusive thoughts (obsessions)
What does SERT gene do
Affects the transport of serotonin
What happens to people’s sert gene with OCD
the sert gene mutates, causing an increase in transporter proteins at a neurons membrane, leads to an increase in the REUPTAKE of serotonin into the neuron which decreases levels of serotonin
How does little serotonin cause ocd
If you don’t have much serotonin floating around in your brain, you might feel depressed or anxious which could lead to ocd
What are candidate genes .
Candidate genes are the genes which create vulnerability for OCD e,g COMT and sent
What does it mean by saying OCD is polygenic
Not a single gene implicates OCD, multiple do. Complex and unclear disorder.
Taylor (2013) meta analysis found evidence of up to 230 different genes involved with OCD
What does aetiologically heterogeneous mean
Different types of OCD, a number of different colonisations of genes
Supporting evidence of biological explanations of OCD
Family studies (Lewis 1936)
Twin studies (nestadt et al 2010)
Family studies
Lewis 1936’ assessed ocd sufferers and found that 37% had parents who also had the disorder. 21% of sufferers also had siblings who had the disorder
Twin studies
Nestadt et al 2010, reviewed twin studies examining OCD, found concordance rate of 68% in identical twins, and 31% of non identical twins
Positives of biological explanation of OCD
- good supporting evidence, but concordance rate is not 100% so environment must play a role
Negatives of biological explanation to OCD
- too many candidate genes which means they can’t provide a useful, predictive value for the disorder
- culturally transmitted, families may be more vulnerable to OCD as the family members may observe and imitate each ither’s behabiour
OFC
Orbitofontrol cortex
Worry circuit
- OFC notices when something is wrong
- OFC sends signals to the thalamus about this that are worrying
- The caudate nucleus (in basal ganglia) is in between and it regulates the signals from OCD, so thalamus doesn’t get hyperactive
Worry circuit for someone with ocd
When caudate nucleus is damaged or abnormal, it fails to suppress worries. Thalamus is alerted which sends signals back to OFC. anxiety and impulsive behaviours occur
Animal Research supporting dopamine to do with OCD
Szechtman et al 198
High dose of drugs enhance dopamine induce movement resembling compulsive behaviours found in OCD (animal study)
Research supporting serotonin role in OCD
Antidepressant drugs that increase serotonin activity have been seen to reduce OCD symptoms
Research supporting worry circuit
Surgery which disconnects the basal ganglia from the frontal cortex can reduce symptoms of severe OCD
3 biological explanations of OCD
SERT
COMT
WORRY CIRCUIT
What does drug therapy aim to do
Increase or decrease levels, or activity of neurotransmitters in the brain
What does SSRIs stand for
Selective serotonin reuptake inhibitor. Work on the serotonin system in the brain. Available in liquid or capsules. Takes up to 3 to 4 months of daily use
3 types of SSRIs
- citalopram
- escitalopram
- fluoxetine
Combination of SSRI and CBT
1 - SSRIs biological intervention. Can reduce symptoms enough to be able to engage with taking therapy
2 - CBT, cognitive intervention, can help sufferers learn to cognitively cope with their obsessions and compulsions
SNRIs
Serotonin-noradrenaline reuptake inhibitors
What do SNRIs do
Increase serotonin and noradrenaline, used to treat OCD for patients who don’t respond to SSRIs
3 drugs to treat OCD
- SSRIs
- SNRIs
- tricyclics
What are tricyclics
Older type of antidepressant. Same effect on serotonin as SSRIs. More severe side effects only used if SSRIs aren’t effective
Positives of drug treatment for OCD
- effective alleviation of symptoms
Clear evidence showing SSRIs are effective in reducing severity of OCD symptoms
Decline by 70% after SSRIs
- cheap compared to therapy, don’t disrupt patients lives, no hard work
negatives of drug treatment for OCD
- side effects, e.g blurred vision
