Explaining OCD (Biological App.) - PSYCHOPATHOLOGY Flashcards
emotional characteristics of OCD
low mood
fear/regret
cognitive characteristics of OCD
obsession
panic/distress
behavioural characteristics of OCD
compulsions
withdrawal/avoidance
what type of disorder is OCD classed as
an anxiety disorder
what are obsessions (within OCD)
internal components - intrusive thoughts
what are compulsions (within OCD)
external components - repetitive behaviours
why do patients with OCD do repetitive compulsive behaviours
they reduce anxiety
what three assumptions are always included in the biological approach
genetics
neuroanatomy
neurotransmitters
three genes included in genetic explanations of OCD
COMT, SERT, neurotransmitters (dopamine and serotonin)
what does COMT produce
an enzyme that degrades dopamine
what type of COMT variant is found in OCD patients
a low activity one
what does the impaired inability to degrade dopamine lead to
higher levels of dopamine in the synapse (particularly after stress)
what does SERT produce
a protein that transports serotonin back to the presynaptic neuron (reuptake)
what type of SERT variant is found in OCD patients
a high activity one
what does removing serotonin quickly result in
lower levels of received and shorter duration of serotonin’s effects
what are the levels of dopamine like in OCD patients
thought to be abnormally high
what are the levels of serotonin activity like in OCD patients
lower amounts
what type of neurotransmitter is dopamine
excitatory
what type of neurotransmitter is serotonin
inhibitory
what is dopamine responsible for
reward, movement, memory
what is serotonin responsible for
appetite, control of behavioural impulses
where is dopamine released into
emotional, executive and memory areas
where is serotonin released into
emotional, memory and muscle-control areas
main function of dopamine
habit forming
main function of serotonin
impulse control
(neuroanatomy) name the abnormal brain circuits within someone with OCD
OFC, thalamus, caudate nucleus
action of the OFC
sends signal to the thalamus about things that are worrying
action of the thalamus
leads to impulse to act and then stop activity when the impulse lessons
action of the caudate nucleus
normally suppresses signals from OFC
action of a DAMAGED caudate nucleus
it fails to suppress signals from OFC
thalamus is alerted about minor ‘worry’ signals
sends signals back to OFC acting as a worry circuit
OCD process summary - dopamine
COMT activity low -> dopamine levels high -> caudate nucleus underaction (exhausted) -> hypervigilance (anxiety) -> obsessive thoughts
OCD process summary - serotonin
SERT activity high -> serotonin levels low -> orbitofrontal cortex overaction -> impulsiveness -> compulsive behaviour
