OCD

what are the DSM-5 categorisations for OCD?

• obsessions (recurring thoughts, images, etc)

• compulsions (repetitive behaviours - e.g. hand washing, counting, etc)

what are some behavioural characteristics of OCD (not needed)

• compulsions are repetitive

• compulsions reduce anxiety

  • behaviours are done in an attempt to reduce the anxiety produced by an obsession

    • for example, if you don’t move the chair so it’s facing the right way, something bad will happen

• avoidance

  • reduce anxiety by keeping away from the situation

what are some emotional characteristics of OCD (not needed)

• anxiety and distress

• accompanying depression

  • low mood and a lack of enjoyment

• guilt and disgust

what are some cognitive characteristics of OCD (not needed)

• obsessive thoughts

  • 90% experience this

  • unpleasant and recurring

• cognitive coping strategies

  • praying, mediation, etc

  • can make them appear more normal

• insight into excessive anxiety

  • the person is aware that their obsessions and compulsions aren’t rational but they still think about the worst-case scenarios that might happen

  • this can cause hypervigilance (extreme alertness)

what is the biological approach to explaining OCD

• genes

  • evidence from twin and family studies suggest the role of genes

• neural

  • genes associated with OCD are likely to impact structures of the brain and levels of key neurotransmitters

explain some of the evidence of the involvement of genes in OCD

• lewis (1936) found 37% of patients had parents with OCD, 21% had siblings with OCD

  • genetic vulnerability

  • exposure to stress in the environment is needed

    • this is the basis of the diathesis stress explanation

    • it suggests that some people have a biological predisposition to develop OCD, but this only happens when there is the right variables in the environment to do so

• the SERT gene (5-HTT) has been implicate in OCD due to its role in transporting serotonin across the synapse

  • leads to low levels of serotonin

• COMT gene regulates dopamine production, and may also be implicated in OCD

  • low activity of gene = high dopamine = OCD

  • suggested by Tukel et al 2013

• OCD is likely to be a polygenetic

  • taylor (2013) suggested that up to 230 genes may be involved in OCD

explain some of the evidence for neural involvement in OCD

• MRI reveals that grey matter in the brain provides support for the worry circuit explanation

  • grey matter = essential tissues in the brain and spinal chord that plays an important part in memory, emotions, and movement

  • in areas of the brain like orbitofrontal cortex, involved in emotion, reward-related, decision making

    • all shows that abnormal anatomical differences can be inherited

• lateral frontal lobes involved in decision making and logical thought may not be functioning properly

• the left parahippocampal gyrus, associated with processing unpleasant emotions, may function abnormally in OCD

• low serotonin prevents normal transmission of mood-relevant information

  • impacts other mental processes

• high dopamine = irrational thoughts

• low serotonin and high dopamine may be the cause of obsessive focused thoughts during periods of low mood

evaluate some of the strengths of the genetic explanation of OCD

• nestadt et al (2010) found 68% of all MZ twins had OCD, while 31% of DZ twins had it

  • increases the validity of the theory

  • suggests that OCD can be partially explained by genetics

• twin studies

  • each twin acts as the “control” for the other twin, which means that each twins individual differences can be accounted for to some extent

  • large samples result in robust quantitive data which creates good reliability for the genetic explanation

evaluate some of the genetic explanation of OCD

• if we ignore the role that the environment plays in the development of a mental illness, a genetic explanation is prone to biological reductionism

  • twins being brought up in the same environment means they’re likely to respond to it similarly to one another

  • if the environment contributes to OCD then a genetic explanation lacks full explanatory power

explain the basics of the biological approach to treating OCD

• drug therapies

  • aim to increase the availability of serotonin in the brain

what are SSRI’s and what do they stand for

• selective serotonin re-uptake inhibitors

• the most common drug prescribed for OCD

how do SSRI’s work

• electrical messengers travel through the presynaptic nerve

• they direct the serotonin in the synaptic vesicles to travel across the synapse into the receptor sites in the postsynaptic nerve

• SSRI’s selectively blocks the reabsorption of serotonin by fitting into the synaptic vesicles

• the aim is to regulate the amount of serotonin in the synapse so that there is just enough to fill the receptor sites

• they don’t fill all of the vesicles so that some of the serotonin can be recycled

• this helps with OCD because it means that the person’s mood is more balanced as there is enough serotonin to keep them calm

  • people with OCD have low availability of serotonin

  • so if we block the reabsorption of serotonin it means that the hormone has to keep travelling in order to continue to regulate the mood

how effective are SSRI’s and SNRI’s in treating OCD

• 70% of patients experience symptom reduction

• SSRI - “first-line treatment”

• SNRI - “second-line alternative”

• effectiveness of these medications is enhanced when combined with CBT

how effective are SSRI’s

• main treatment

• increase serotonin levels in the brain

  • reduce anxiety levels and regulates mood

• studies show that they are more effective than a placebo

  • this is shown in a meta analysis done by the National Institutes of Health

how effective are SNRI’s

• when patients experience sexual side effects from SSRI’s, SNRI’s are considered as a viable alternative

• SNRI’s block the re-uptake of serotonin and norepinephrine

  • potentially providing broader symptom relief

how effective is combined treatment for OCD

• effectiveness of SSRI’s is often better when paired with CBT

  • CBT helps them to learn different coping strategies

    • helps manage obsessions and compulsions

how do tricyclics work in treating OCD

• OCD means you have high dopamine and low serotonin levels

• tricyclics work to block re-uptake of serotonin (meaning they work similarly to SSRI’s in that respect)

• if there is more serotonin, it can help to reign in the effects of dopamine

• too much dopamine and not enough serotonin can lead to overexcitement

• where as a balance of the two can help to control the effects of dopamine, helping to keep people with OCD calm

• tricyclics also block re-uptake of noradrenaline which helps to increase levels of this neurotransmitter in the brain (like serotonin)

what are some strengths of the biological treatments of OCD

• cost effective

• widely used

• widely available

  • more available than CBT

  • more people can go back to work faster than if they were to partake in a series of CBT sessions

  • there is less of an effect on the economy

• there is good research support for the efficiency of drug therapy

  • soomro et al (2009) reviewed 17 studies which compared drugs to placebos

  • found 70% effectiveness for SSRI’s

  • as it was a meta-analysis, it has strong validity

  • griest et al (1995) also did a meta analysis in which they reviewed placebo-controlled trials

  • this found that the drugs were more effective than the placebo

what are some limitations of the biological treatments for OCD

• drug therapy can only be used for short time periods

  • with this therapy, it is hard to tell whether we are treating the symptoms of OCD or the cause

• there are side effects to drug therapy

  • SSRI’s = blurred vision, loss of libido, irritability, indigestion, sleep disturbance, heart related problems

  • BZ’s (benzodiazepines - anti-anxiety drugs) = drowsiness, slurred speech

• goldacre (2013) found that drug companies selectively publish positive outcomes for the drugs their sponsors are selling

  • this is unethical

  • lessens the validity

  • don’t know if the drug is truly effective