psychopathology- biological approach to explaining and treating ocd

Question 1

what are the 2 genetic explanations

Answer 1

COMT gene
SERT gene
diathesis stress

Question 2

the genetic explanations focus on the meaning that individuals inherit ….

Answer 2

specific genes from their parents that are related to the onset of OCD

Question 3

what is the comt gene explanation

Answer 3

it is involved in the productions of COMT which regulates the production of the neurotransmitter dopamine which is implicated in ocd.

one allele of the comt gene has been found to be more common in ocd patients that without people without.

this variation produces LOWER activity of the comt gene and so there are higher levels of dopamine

Question 4

what is the SERT gene explanation

Answer 4

this gene affects the transport of serotonin > it creates lower levels of it

low levels of S are implicated in ocd.

one study found a mutation of this gene in two unrelated families where six of the seven family members had ocd

Question 5

what is the diathesis stress explanation

Answer 5

it suggests that the presence of a specific gene allele/mutation only creates a vulnerability (diathesis) for ocd (as well as other conditions eg depression)

and that the condition only presents itself when prompted to by a stressor eg trauma

and so people might possess the comt/sert gene variations but have no symptoms because the condition hasnt been manifested

Question 6

what are the 2 neural explanations

Answer 6

abnormal levels of neurotransmitters

abnormal brain circuits

Question 7

what is the abnormal levels of neurotransmitters explanation (dopamine bit)

Answer 7

thought that abnormally high D levels in those with ocd.

this is based on animal studies where high doses of drugs that enhance D levels were injected and this induced stereotyped movements resembling the compulsive behaviours found in ocd patients

Question 8

what is the abnormal levels of neurotransmitters explanation (serotonin bit)

Answer 8

lower levels of S are associated with ocd.

based on fact that antidepressant drugs that increase S activity have been shown to reduce ocd symptoms VS antidepressants that have less effect on S do not reduce ocd symptoms

Question 9

what is the abnormal brain circuits explanation

(what are the parts, what is the worry circuit, how is it explained in pet scans)

Answer 9

several areas in the frontal lobe are abnormal in people with ocd

eg caudate nucleus

so orbitofrontal cortex DOES send signals to the thalamus about things that are worrying eg potential germ hazard

so when caudate nucleus is damages it fails to suppress minor “worry” signals and so thalamus IS alerted

this then sends signals back to ofc in a worry circuit

pet scan when ocd symptoms are active > shows more activity in ofc

active eg when a germ obsessive holds a dirty cloth

Question 10

which neurotransmitter is associated with comt gene and the sert gene

Answer 10

comt- dopamine
sert-serotonin

Question 11

what is the abnormal levels of dopamine explanation based on

Answer 11

animal studies

Question 12

what is the abnormal levels of serotonin explanation based on

Answer 12

antidepressants

Question 13

what does the caudate nucleus normally do

Answer 13

suppress signals from the orbitofrontal cortex (OFC)

Question 14

what is involved in the worry circuit

Answer 14

orbitofrontal cortex (ofc) and thalamus

Question 15

what is the abnormal brain circuits explanation based on

Answer 15

pet scans

Question 16

what neurotransmitters are associated with the brain regions that are abnormal

Answer 16

serotonin > abnormal > caudate nucleus and ofc malfunction

dopamine for basal ganglia (containing caudate nucleus) abnormal levels > malfunction

Question 17

what is the biological approach to treating ocd

Answer 17

drug therapy

Question 18

what are the types of drug therapy for treating ocd

Answer 18

antidepressants (SSRIs and tricyclics)

antianxiety drugs

there are also some other drugs (antibiotic d-cycloserine)

Question 19

what does SSRI stand for

Answer 19

selective serotonin reuptake inhibitors

Question 20

why are the antidepressants SSRIs used to treat ocd

Answer 20

both depression and ocd sufferers have low levels of serotonin, increasing S therefore treats both.

increasing S normalises the worry circuit.

used to reduce the anxiety associated with ocd.

they increase levels of S which regulates mood and anxiety

Question 21

how do SSRIs work at a synapse

Answer 21

S is released into synapse on one neurone and targets receptor cells on receiving neurone at receptor sites and is then reabsorbed by the initial neurone

so taking an SSRI increases stimulation to the receiving neurone so the reuptake is inhibited

Question 22

how do the antidepressants tricyclics work

Answer 22

they block the transporter mechanism that reabsorbs both S and noradrenaline into the presynaptic neurone.

so more of the neurotransmitters are left in the synapse prolonging their effect and easing transmission of the next impulse.

+ they can target more than one neurotransmitter

-greater side-effects so used if SSRIs are not effective

Question 23

what are anti-anxiety drugs (benzodiazepines), how do they work

Answer 23

eg valium, xanax, diazepam

they slow the activity of the cns by enhancing GABA, a neurotransmitter than when released has a quietening effect on the brain.

because it reacts with GABA receptors on receiving neurones, so when GABA binds with receptor it opens chloride channel > chloride into neurone > makes it harder for neurone to be stimulated by another neurotransmitter > slowing activity > more relaxed

Question 24

how can the antibiotic d-cycloserine be used for treating ocd

Answer 24

reduces anxiety so effective for ocd especially when used in conjunction with psychotherapy.

it is normally used for tb treatment but has been seen to enhance GABA transmission > reduce anxiety