obsessive-compulsive disorder Flashcards
Characterstics of ocd, biological explanations, biological treatments for ocd
What is ocd defined as?
ocd is a condition characterised bey either obessions (recurring thoughts, images etc.) and/or complusions (reptitive behaviours).
DSM-V catergories of ocd:
ocd and related disorders:
* Trichhotillomania: complusive hair pulling
* Excoriation disorder: complusive skin picking
* Hoarding: complusive gathering of possessions and abllity to part eith anything, regardless of its vaule.
What is the common factors between the catergories of ocd?
- All have repetivie behaviours accompained by obsessive thinking
- All involves anxiety (similar to phobias) and irrational thinking.
Behavioural characterstics of ocd
- Reptitive complusions: compelled to repeat a behaviour
- Complusions reduce anxiety:majority of sufferers perform complusions to reduce the anxiety produced by the obbessions
- Avoidance: avoiding situations that trigger the anxiety
Emotional Characterstics of ocd
- Anxiety and distress- unpleasant and frightening thoughts creates a popwerful anxiety and the urge to do the complusion making them feel overwhelmed.
- Accompanying depression- the anxiety can be accompained by low mood and lack of enjoyment of activites. complusive behaviour relief os only temporary.
- Gluit and disgust- irrational gluit or disgust may be directed at something external or the self.
Cognitive characteristics of ocd:
- Obsessive thoughts: obessions are cognitions and recur over and over again. Unpleasant.
- Cognitive coping strategies: Obsessions are the major cognitive aspect of ocd but people response by adopting coping strategies to help manage anxiety, this can appear abnormal and distract from everyday activites.
- They are aware that their obessions and complusions are not rational. Catastrophic thoughts result in justifying anxieties so they tend to be hypervigilant.
what is the ocd cycle?
Obessions (unwanted distressing thoughts, urges and mental images) -> anxiety (distress, fear, worry or digust) -> compulsions (behaviour performed to help make the anxiety go away)-> Relief (only temporary and obessions return pertpertuating a cycle).
What is the genetic explanation for ocd?
Some people may be predisposed to develop ocd due to their genetic make-up- this is called genetic vulnerability.
What did Lewis (1936) find out about ocd
He found evidence that suggests genetic vulnerabillity for ocd runs in families.
* 37% ocd patients had parents with ocd.
* 21% had siblings with ocd.
What did Nestadt et al. (2010) find out ocd?
Twin study showed that 68% of identical twins shared ocd and 31% non-identical twins. This strongly suggests there is a genetic influence for ocd.
What does the diathesis-stress model say about ocd?
The diathesis-stress model states that the genetic vunerability only triggers ocd if an environmental stressor is experinced (e.g. stressful or tramuatic life event).
What are candidate genes?
Candidate genes are specific genes thought to make an individual vunerable to a particular disorder or disease.
What is thought to be the candidate gene for OCD?
gene 5HT1-D beta
What is gene 5HT1-D beta involved in?
Transporting the neurotransmitter serotonin across synapses. Therefore the serotonin system is believed to be involved in ocd.
What studies are there that support a genetic link to ocd?
- Lewis (1936)
- Nestadt et al.
What does polygenic mean?
A trait is not caused by one gene, but by many genes.
What studies provide supporting evidence that ocd is polygenic?
Taylor (2013) found evidence from previous studies that up to 230 different genes may be involved in ocd.
What do the other genes linked to ocd do?
Those associated with the action of serotonin and dopamine- neurotransmitters believed to play a role in regulating mood.
What does aetiologically heterogenous mean?
The trait is caused by different genes in different people.
What evidence is there to support the belief that OCD is aetiologically heterogenous?
Different types of OCD, e.g. hoarding disorder and religious obession, may be the result of particular genetic variations, or particular sets of genes.
Strengths of the genetic explanations for ocd
There is strong supporting evidence that there is genetic vunerability can increase the likelihood of developing ocd. e.g. Nestadt et al.
Weaknesses of the genetic explanations for ocd
- Genetic explanations do not consider that environmental facors can also increase the risk of developing ocd, as stated by the diathesis-stress model.
- Cromer et al. (2007) found over 50% of ocd patients in their sample had a tramuatic event in their past. Those with more than one tramua had more severe ocd. This suggests that genetic vulneralbity only provides a partial explanation for ocd.
What are neural explanations?
The view that physcial and psychological characteristics are determined by the behaviour of the nervous system (brain and neurons).
What do genes associated with ocd affect abnormally?
- Levels of neurotransmitters
- Certain brain structures