OCD Flashcards
Behavioural characteristics of OCD
- Compulsions (Repetitive behaviour)
- Avoidance (of triggering situations)
Emotional characteristics of OCD
- High anxiety
- Embarrassment/shame (they are self aware)
- Disgust (towards source of obsession or at self)
Cognitive characteristics of OCD
- Obsessions/Irrational beliefs
- Awareness that Behaviour is Irrational
- Hypervigilance/Selective attention to source of OCD
Biological approach to OCD
OCD is caused by genetics and biochemicals
Polygenic
More than one gene is required to manifest the trait
What are the multiple genes that could cause a polygenic trait called
Candidate genes
COMT gene
Regulates the production of dopamine, produces higher levels in OCD patients
SERT gene
Affects transport of serotonin, lower in OCD patients
Genetic Explanation Evaluation
+ Nestadt et al found 68% concordance rates for monozygotic twins compared to 32% in dizygotic
+ Ahmari found a common gene in mice than display ritualistic behaviour
- Half of OCD cases are related to previous trauma, so this does not account for cases where there is no family history of OCD
High dopamine effects
- Hyperactive basal ganglia brain region, which causes repetitive motor actions (compulsions)
Low serotonin effects
- Serotonin plays a key role operating the caudate nucleus in the basal ganglia
- Low levels cause poor function in caudate nucleus
- Low levels can cause obsessions
Neural explanation evaluation
+ Antidepressants that increase serotonin levels has been shown to reduce OCD symptoms
+ Has positive applications, as these antidepressants can ‘cure’ OCD
- The neurotransmitter levels might be a symptom more than the cause
SSRIs
Selective Serotonin Re-uptake Inhibitors (includes Prozac and Fluoxetine)
How do neurotransmitters send messages
Presynaptic neurone releases neurotransmitter, travels across synaptic cleft to convey the message to the post synaptic neurone, and then is reabsorbed by the presynaptic neurone
SSRI effect
Prevents the reabsorption of serotonin, so it remains in the synapse longer and continues to stimulate the postsynaptic neurone. This reduces anxiety
How long does daily SSRI use take to have an impact on symptoms
3-4 months
SSRI Evaluation
+ Soomro reviewed 17 studies comparing SSRI to placebo, SSRIs are shown to be more effective, especially when done with Cognitive Behavioural Therapy
+ 70% of patients experience decline in OCD symptoms while on SSRIs
- Severe side effects (indigestion, blurred vision, loss of sex drive)
Benzodiazepines (BZs)
- Anti-Anxiety
- Slows the activity of the Central Nervous System (CNS) by enhancing the activity of GABA
GABA
- Has an inhibitory effect on neurones
- Reacts with GABA receptors on the outside of neurones
- Opens a channel to increase flow of chloride ions
- Chloride ions make it harder for any other stimulation
- Leads to relaxation
Benzodiazepines Evaluation
+ Reduces anxiety levels quickly and gives immediate relief
- Side effects: drowsiness, depression, unpredictable interaction with alcohol
- Ashton: long term BZ users are very dependent, and withdrawal leads to high anxiety
- Body gets used to the drug, so larger doses are needed
