OCD and how to treat it

what are the 3 levels of biology that effect ODC

genetics brain chemistry brain structure

what does the genetic explanation look at

impact of genes on OCD

OCD is Aetiological heterogeneity what does this mean

different combinations of genes may cause the disorder in different people.

OCD is cause by more than one gene what is this called

Polygenic

name 2 example of genes that can cause OCD

The COMT gene

The SERT gene

what does the SERT gene do 

The SERT gene is linked to the efficiency of transport of serotonin (and can cause low levels of serotonin)

what does the COMT

the COMT gene is associated with the regulation of dopamine

What is a piece of evidence that back up the genetic explanation

with OCD the more closely people are related the more likely they are also to have OCD. first degree relative had a concordance rate of 10% much higher than the average population which is 2 %. Dizygotic twins who share 50 % of there genetic make up have a concordance rate of 31% and monozygotic twins who share 100 % of there genetic make up have a concordance rate of 68%. This suggest its in herniated.

one limitation is that family studies doesn’t automatically mean causation

It might not be the shared genetics behind the high concordance rates instead the facts the close family members live in very similar environments and are raised in similar conditions. identical twins have a concordance rate of 68% not 100 which implies that there are other non genetic factors which must be the role of the environment

another limitation that its not just genetic but environment plays a role

The diathesis stress response is a better explanation for OCD. Individual inherit genetic vulnerability to OCD (diathesis). However there has to be an environmental trigger (stressor) such as a traumatic life experience for OCD to appear Cromer showed that 54% of his 265 ps had experienced traumatic life events. Those pd siad that there symptoms had become worse

neural explanation

include biochemical causes an imbalance in neurotransmitters and larger neural structures in the brain that are made of many neurons.

what larger neural structure that can cause OCD

the worry circuit

what makes up the worry circuit

1. orbital frontal cortex OFC

2. basal ganglia part of the caudate nucleus

3. thalmaus

how does someone with OCDs worry Cricut differ from those of normal people

normally the basal ganglia filters out minor worries coming from the OFC. However the basal ganglia is hyper active and even small worries get to the hypothalamus. the worry is then passed back to the OFC forming a loop which creates there obsessive thoughts.

why does the worry circuit result in people doing repetitive action or compulsions

These are an attempt to break the loop. the compulsion provide temporary relief however the worry circuit will soon begin

what is another neutral structure that can cause OCD

The pharahipocampal gyrus is responsible for regulating and processing the negative and unpleasant emotions and its seen to behave abnormally in those who have OCD

evidence in support of neural structures and limitation

Neural explanations for OCD have been supported by brain scans. These are advantageous as they show visual evidence of the OFC being over-active in OCD patients compared with control groups and that brain structures of OCD patients such as the parahippocampal gyrus differ compared to non-OCD sufferers. For example, Gilbert provided empirical evidence to support that OCD patients have a larger thalamus which is a part of the brain linked to cleaning, checking and other safety behaviours.

Researcher cant be sure if this hyperactivity causes OCD or is it is a consequence of having OCD

What does the chemical explanation involve

the effect of neurotransmitters hormones chemical on OCD

what are the 2 most important neurone transmitters

serotnin and dopamine

effect of serotonin

Comer (198) reported that serotonin played a key role in the operation of the OFC and caudate nuclei therefore it may be that abnormal levels of serotonin cause these areas to malfunction.

thought to cause obsessive thoughts. Its likely to be caused by the removal of neurone transmitter to fast from the synapse before it can transmit a signal to influence the postsynaptic neurone. It seems this process happens quicker in those who have OCD. The SERT gene is responsible for serotonin transportation in synapes this is one the genes that has been linked to causing OCD

Effects of Dopamine

Dopamine is the main neurotransmitter of the basal ganglia and high levels can cause over activity in this region

one treatment is SSRIs what do they stand for/ do

Selective Serotonin Reuptake Inhibitors. This means they slow the reuptake of serotonin so more time is spent in the synaptic cleft this means that its more likely to effect the postsynaptic neuron. This decreases anxiety by regulating the worry Cricut

evaluation about serotonin

meta analysis by Soomro showed that SSRIs are more effective than placebos suggesting there is a biological element to OCD. Despite changing the levels of serotonin in synapse in hours it take weeks to see an effect on symptoms. 40 to 60 percent of ps show no or partial improvement. This shows that whilst serotonin has a role in OCD it isn’t the main factor causing it. It also shows that serotonin might play a smaller and larger role depending on the person