OCD Flashcards
what is OCD
an anxiety disorder, sufferers experience persistent and intrusive thoughts occurring as an obsession, compulsions or a combination of the 2
what are obsessions
- innapropriate ideas and visual images that arent based on reality
- persistent thought, idea, impulse or image that is experienced repeatedly
- INTERNAL components
what are compulsions
- uncontrollable urges to repeatedly perform tasks and behaviours
- repetitive and rigid behaviour or mental act that a person feels drive to perform in order to prevent or reduce anxiety
- thoughts somthing bad will happen
- EXTERNAL components
the ocd cycle
obsession–> anxiety–> compulsions–> relief
what is concordance rate
measure of genetic similarity e.g. the rate one twin will have a disorder if the other twin has it
what is a nerotransmitter
chemical substances that play an important role in the working of the nervous system by transmitting nerve impulses across a synapse
what is a gene
part of the chromosome of an organism that carries info in form of dna
what is dopamine
a key neurotransmitter in the brain, which effects on motivation and drive
what is serotonin
another neurotransmitter, which is believed to have an affect on mood regulation
what are the two biological explanations for ocd
genetic and neural
what is the genetic explanation
- inherited from your parents, if you inherit certain genes you may be more likely to have ocd
what are the 2 types of twins
identical- MZ
- expect 100% concordance rate
non identical- DZ
- expect a 50% concordance rate
what does polygenic mean
more than one gene, different variations
for ocd there are 230 genes identified to link ocd which means their are different extremes
as you could inherit gene from one parent and other parent, the combination may give a different type of ocd
COMT gene
- production of enzyme that regulates function of dopamine and helps reduce its action
- people with ocd have a mutation of COMT gene- may not perform job as it should
- variation in the comt gene decreses amount of comt available therefore dopamine is not controlled; way too much dopamine
- dopamine gets more time to bind so ends up being too much which raises dopamine levels, causes behaviour effect- ocd
NOT PRODUCE ENOUGH , LESS REMOVED, INCREASE DOPAMINE
SERT gene
- affects transport of serotonin, creating low levels of it
- transports serotonin away from synapse
- mutation increase, more serotonin removed
- over time= low levels of serotonin
- not enough to bind to receptors
PRODUCES ENOUGH, MORE REMOVED, DECREASES SEROTONIN
low serotonin= ocd
Nestadt et al (2000)
- 80 patients with ocd and 343 of near relatives compared with control group without mental illnesses and their relatives
- strong link with near family- 5 x greater risk if had first degree relative
- nestadt et al (2010)- twin study (68% MZ, 32% DZ)
what is a meta analysis
study combining results of lots of studies
what is the neural explanation
- includes neurotransmitters and structures of the brain
- imbalance in neurotransmitter serotonin, related to ocd
serotonin= chemical that regulates mood
ocd patients= low serotonin - serotonin removed too quickly from synapse before impulse has been passed on
- not much serotonin floating around in your brain- obsessive thougts
dopamine - abnormally high in individuals with ocd
- high levels of dopamine have thought to influence concentration
- ocd individuals experience inability to stop focussing on obsessive thoughts and repetitive behaviours
- high levels of dopamine linked to conpulsive behaviour
research evidence
pigott et al (1992)
- antidepressant drugs that increase serotonin activity have been seen to reduce OCD symptoms
the frontal lobe
- part of frontal lobe called ofc (orbital frontal cortex)
deals with executive functioning, making decisions
if it doesnt work it can be linked with conditions such as ocd
decision making impaired
the OFC
for a person with ocd, if ofc is over activated, continue doing action e.g. washing hands repeatedly
what do pet scans show
show heightened activity in parts of the frontal cortex known as the ofc
what is the basal ganglia
- group of structures including caudate nucleus, thalamus in th brain and is responsible for psychomotor functions, hypersensitivity of the basal ganglia may result in repetitive movements
abnormal brain circuits
brain dysfunction
- OFC circuit
ofc sends ‘worry’ signals
these signals are normally suppressed by the caudate nucleus
in ocd the caudate nucleus is thought to be damaged so it cannot suppress the signals which become increasingly excited- increasing compulsive behaviour and anxiety (maybe dopamine pathway and levels also implicated)
- surgery which disconnects the basal ganglia from the frontal cortex can reduce symptoms of severe ocd
strengths of the biological explanation for ocd
- its testibilty via neuroscience research, evidence for genetic and neurotransmitter involvement
- anti depressents typically work by increasing levels of the neurotransmitter serotonin- these drugs effective in reducing the symptoms of ocd and provide support for a neural explanation of ocd
weaknesses for the biological explanation
-deterministic because they ignore the individuals ability to control their own behaviour which in turn may effect their biochemistry levels
- approach can also be criticised for ignoring environmental influences, e.g. people not born with ocd they may learn it from their environment through the process of classical and operant conditioning
- findings from neural explanations are problematic as drugs used to affect serotonin such as SSRIs may decrease the symptom but that does not mean that an imbalance of serotonin was the cause in the first place
treatment for ocd
SSRIs = reuptake is inhibited
- work by binding to the reuptake chanel as a result they inhibit the reuptake process
- prevent serotonin from being reuptaken
- leaves more serotonin, less reuptaken, more in the synapse and gives more opportunity for serotonin to bind to receptors, signal continues
BZs
- anxiety release medication
- GABA (neurotransmitter) naturally inhibituary
- enhance GABA
- GABA binds to receptor on post synaptic neuron
- when it binds it opens up receptors where BZ ends up enhancing inhibituary effect
- BZs work very quickly
- BZ inhance gaba in calming down
- less anxiety associated with ocd
treatment for ocd
SSRIs = reuptake is inhibited
- work by binding to the reuptake chanel as a result they inhibit the reuptake process
- prevent serotonin from being reuptaken
- leaves more serotonin, less reuptaken, more in the synapse and gives more opportunity for serotonin to bind to receptors, signal continues
BZs
- anxiety release medication
- GABA (neurotransmitter) naturally inhibituary
- enhance GABA
- GABA binds to receptor on post synaptic neuron
- when it binds it opens up receptors where BZ ends up enhancing inhibitory effect
- BZs work very quickly
- BZ enhance gaba in calming down
- less anxiety associated with ocd
