PP - OCD Flashcards
what is OCD
obsessive compulsive disorder - an anxiety disorder
what is an obsession
persistent, intrusive and recurring thoughts or images
what are compulsions
repetitive and ritualistic behaviours that often occur as a result of obsessions
who experiences what with OCD
70% have obsessions and compulsions
20% experience obsessions
10% experiences compulsions
1.2% of the world has OCD
what is the OCD cycle
what are DSM-5 disorders grouped with OCD
- trichotillomania: compulsive hair pulling
- hoarding disorder: compulsive gathering of possessions and the inability to part with anything regardless of value
- excoriation disorder: compulsive skin picking
what are the cognitive characteristics of OCD
- obsessive thoughts
- awareness of irrational, excessive anxiety
- may partake in strategies to deal with obsessions e.g. praying
behavioural characteristics of OCD
- avoidance of the anxiety causing stimulus
- compulsive behaviours
emotional characteristics of OCD
- accompanying depression
- guilt and disgust
- anxiety and distress
what are the biological explanations of OCD
- genetic explanation
- brain structure
- neurotransmitters
what is the genetic explanation of OCD
- OCD tends to run in families suggesting a genetic link
- biopsychologists investigate concordance rates for traits of OCD between family members
what occurs during twin studies in the genetic explanation
- compares MZ twins with DZ twins
- if a trait has a higher biological basis - concordance would be higher for MZ, higher environmental basis DZ would be higher
NEVER 100% CONCORDANCE
what are gene mapping studies in the genetic explanation
- compares the genetic material from OCD suffers with non-sufferers
- indicates a genetic link but is likely to be polygenic
- Lenane et al saw a prevalence of OCD in related family members
what is a problem with the genetic explanation
- no one’s really sure what exactly is being inherited
- never get 100% concordance
- research suggests some forms of OCD are more genetic than others
how does the brain structure explain OCD
the “worry circuit” has a fault - causing irrational responses
what is the “worry circuit”
- the orbitofrontal cortex sends signals to the thalamus via the caudate nucleus about things that are worrying
- to get to the caudate nucleus, the cingulate cortex acts as a relay system between the two
- the caudate nucleus usually regulates information from the OFC
- when the caudate nucleus is damaged, it fails to suppress minor worry signals so the thalamus is alerted
- this sends signals to the OFC and confirms the worry
difference between the orbitofrontal cortex in normal brain vs. OCD brain
N: integrates sensory info, makes decisions and anticipates rewards and punishments
OCD: detects an error when there isn;t one
difference between the cingulate cortex in normal brain vs OCD brain
N: adds emotional response to thoughts
OCD: adds emotions like disgust and guilt to anxious thoughts
difference between the caudate nucleus in normal brain vs. OCD brain
N: processes and filters information, removes unwanted thoughts - stabiliser
OCD: fails to filters unwanted thoughts
differences between the basal ganglia in normal brain vs. OCD brain
N: controls movements, thinking and judgement
OCD: causes reflexes or repetitive behaviour
what are neurotransmitters
chemical messengers that carry, boost and regulate signals between neurons and other body cells
what is the neurotransmitter linked to OCD
serotonin - sends mood relevant information - if it does not take place, then mood and mental processes can be affected
why do we think serotonin is linked to OCD
- serotonin is said to play a very active role in the orbitofrontal cortex and caudate nucleus
- low levels may cause abnormal functioning (OCD)
specific genes related to OCD
COMT gene - reduces the action of dopamine
SERT gene - affects the transport of serotonin
what are the 3 drug treatments for OCD
- antidepressants (SSRIs)
- SNRIs
- benzodiazepines (BZs)
characteristics of SSRIs
- most common form of treatments for OCD
- inhibit serotonin reuptake
- dosage for OCD is higher than for depression
- some people do not respond to this medication
characteristics of SNRIs
- inhibit serotonin and norepinephrine reuptake
- only used if SSRIs don’t work as they have more side effects
- drugs include amitriptyline
characteristics of BZs
- anti-anxiety drugs
- increase the action of neurotransmitter GABA
- inhibitory neurotransmitter - “slows down” the brain
strengths of biological treatment of OCD
- Soomro et al discovered that drugs were more effective than placebos - they actually work
- little effort in taking a pill and not very intrusive
- doesn’t require any motivation to get better - CBT does
limitations of biological treatment for OCD
- side effects for SNRIs and BZs can be very harmful
- little long term evidence for treating OCD - relapse in often common
- selective publication often leads doctors to mistreat patients
what does the COMT gene control
reduces the action of dopamine
what does the SERT gene control
affects transport of serotonin
