Biological explanation for OCD

1. Biological explanation for OCD Psychopathology: The biological approach to explaining OCD: genetic and neural explanations

2. Learning outcomes • By the end of the session you will be able to: • Describe the biological explanation for OCD, including genetic and neural explanations • Consider evidence that supports the explanation • Evaluate the two explanations considering alternative ideas • Describe the biological treatment for OCD • Explore evidence for drug therapy and develop an evaluation for the treatment

3. Recap Characteristics • https://www.youtube.com/watch?v=qPCsaNresXw

4. Basic assumptions of biological approach Remember these? • Everything psychological is at first biological • The approach investigates how biological structures and processes within the body impacts on behaviour. • Much of human behaviour has a physiological cause which may be genetically or environmentally altered. • Genesaffect behaviour and influence individual psychological differences between people. Evolutionary psychology considers genetic influences in common behaviours • Psychologists should study the brain, nervous system and other biological systems, e.g. hormones, chemicals acting on the brain

5. Genetics… • a genetic component to OCD predisposessome individuals • If a person develops OCD, partly due to their genes - may explain why patients often have other family members with OCD Nestadt et al (2000) first degree relatives (parents, siblings, children) 11.7% chance of developing disorder 2.7% first degree relatives in control group (no OCD) Twin studies are used to explore this explanation….

7. Twin studies With twin studies there are 2 main methods comparing concordance rates of monozygotic twins with dizygotic twins Comparing monozygotic twins reared together with monozygotic twins reared apart

8. Adoption studies With adoption studies we tend to compare the adopted child with the biological mother and the adoptive mother to see which correlation coefficient is highest E.g. Child and adoptive mother 0.42 Child and biological mother 0.72

9. research • Bellodi et al (2001) used evidence from twin studies and family studies - showed that close relatives are more likely to have the disorder than more distant relatives. • Mckeon and Murray- patients with OCD are morl likely to have first degree relatives who suffer from anxiety disorders. • Pauls et al- there is a much higher percentage of OCD sufferers in relatives of patients with OCD than in the control group without OCD. • Miguel et al (2005) looked at identical twins… if one twin has OCD, the other has 53% - 87% chance of having OCD too. • Non identical twins – 22% - 47% chance

10. Argued that upbringing between pair of identical twins and pair of non identical twins is minimal so environment cannot be used as an explanation • Environment is implicated to a point… • Non identical twins are no more similar than siblings but research is suggesting that they are more likely to get OCD if one of the pair has it • So what is the difference between non identical twins and siblings??? • Born at the same time • Environments are much more similar • Share similar traits?

11. Genetic explanations cont. • Research has suggested that Candidate genes are implicated in the development of OCD. • A possible candidate gene is the SERTgene which is involved in regulating serotonin, a neurotransmitter which facilitates message transfer across synapses. • Another possible candidate gene is the COMTgene – this regulates the production of dopamine • Dopamine effects motivation and drive

13. Combination? • But…. Does everyone in a given family gets OCD?? • No… so there must be additional factors • E.g. The diathesis–stress model suggests that people gain a vulnerabilitytowards OCD through genes • but • an environmental stressor is needed… such as a stressful event, e.g. a bereavement OCD is thought to be polygenic–its development is not determined by a single gene but a few (maybe as many as 230 genes, Taylor, 2013) – suggesting that there is little predictive power from this explanation

14. Evaluation of genetic explanations • Genetics • S – Lots of evidence to suggest there is a genetic component to the disorder. One of the best sources of evidence for the importance of genes is twin studies (Nestadt – 2010) • C - Family studies could also be used to explain environmental influences • C - Close relatives of OCD sufferers may have observed and imitated the behaviour (SLT) • L - It is difficult to untangle the effects of environment and genetic factors

15. Evaluation of genetic explanations • Candidate genes • S - Candidate genes are ones which, through research, have been implicated in the development of OCD. • L - There are too many genes involved • L - Psychologists have not been successful at pinning down all the genes involved • C - Each genetic variation only increases the risk of OCD by a fraction suggesting there may be other explanations

16. Evaluation of genetic explanations • Combination of genes and environment: • Individuals may gain a vulnerability towards OCD through genes that is then triggered by an environmental stressor. • S- Cromer (2007) found that over half the OCD patients in their sample had a traumatic event in the past, and that OCD was more severe in those with more than one trauma • This means that it may more productive to focus on environmental causes as it seems that not all OCD is entirely genetic in origin

17. Neural explanations • The genes associated with OCD are likely to affect the levels of key neurotransmittersas well as structuresof the brain • These are neural explanations Certain brain circuits may be abnormal Abnormal levels of certain neurotransmitters

18. Recap of neurotransmitters - serotonin • Serotonin appears to be the main neurotransmitter associated with OCD • Serotonin= implicated in sleep, memory, emotions, appetite and social and sexual behaviour • Plays a part in preventing repetition of tasks • A lack of serotonin would therefore prevent the ability to inhibit the repetition of tasks…. So repetition would occur

19. Neural explanations • Neuroimaging (brain scans) techniques allow comparisons to be made between normal and abnormal brain patterns • Basal ganglia - implicated in OCD • This area of the brain is responsible for innate psychomotor functions Wise and Rapoport (1989) proposed the hypersensitivity of the basal ganglia gives a rise to the repetitive motor behaviours seen in OCD, for example, repetitive washing/cleaning/checking

20. Neural explanations • Other brain areas believed to be involved in OCD include the orbitofrontal cortex (OFC) and the thalamus • The thalamusis a brain area whose functions include cleaning, checking and other safety behaviours.

21. Neural explanations The orbital frontal cortex The OFC is involved in decision making and worry about social and other behaviour. In OCD the OFC and the thalamus are believed to be overactive. An overactive thalamuswould result in an increased motivation to clean or check for safety. If the thalamus was overactive the OFC would also become overactive as a result. An overactive OFC would result in increased anxiety and increased planning to avoid anxiety.

22. Evaluation of neural explanations • The role of neurotransmitters • A - Allows medication to be developed which helps sufferers. • L - Drugs are not completely effective • C - Just because administering SSRIs decreases OCD symptoms does not mean that this was the cause in the first place • L - There is time delay between taking drugs to target the condition and any improvements being made and yet the chemical imbalance is addressed in hours

23. Evaluation of neural explanations • Areas of the brain • A / S - Advances in technology have allowed researchers to investigate specific areas of the brain more accurately, and OCD sufferers do seem to have excessive activity in the orbital frontal cortex • E - Cleaning and checking behaviours are "hard-wired" in the thalamus • L - The repetitive acts (compulsions) may be explained by the structural abnormality of the basal ganglia but not necessarily the obsessional thoughts. • C - There are inconsistencies found in the research as no system has been found that always plays a role in OCD • C - These neural changes could be as a result of suffering from the disorder, not necessarily the cause of it

24. TASK – 5 mins • In your packs… OCD can be explained by the two process model. In your notes, apply this model to OCD • This can be part of your evaluation … Conflicting Evidence

25. Biological treatment for OCD Psychopathology: The biological approach to explaining treating OCD: drug therapy

26. Drug therapy Common used biological therapy for anxiety disorders is drug therapy Assumes that there is a chemical imbalancein the brain Can be corrected by drugs - either increase or decrease the levels of neurotransmitters in the brain

27. SSRI (Selective Serotonin Reuptake Inhibitors) • Standard medical treatment used to tackle the symptoms of OCD are SSRIs • SSRIs work on increasingcertain neurotransmitter in the brain by preventing the re-absorption of serotonin. • By preventing the re-absorption of serotonin, SSRIs effectively increase its levels in the synapse and thus continue to stimulate the post-synaptic neuron • Serotonin in the post synaptic neuron – regulation of preventing repetition of tasks

29. Combining SSRIs with other treatment • Drugs are often used alongside cognitive-behavioural therapy (CBT) • Drugs reduce the sufferer’s emotionalsymptoms, such as anxiety or depression • Therefore the patient can then engagemore effectively with CBT • Some sufferers may respond best to CBT alone without the need for medication

30. Alternatives • Sometimes an SSRI is not effective….after three to four months the dose can be increased or it can be combined with other drugs • Patients respond differently to different drugs and sometimes alternatives work well for some people and not at all for other, e.g. tricyclics, SNRIs

31. Evaluation of drug therapy for ocd • Using your text books, complete the evaluation table on pg 37 in your packs using these headings to help: Drugs can have side-effects … Drugs may not treat the causes… OBB As with all drugs, relapse rates are apparent… Drug therapy is effective at tackling OCD symptoms… Drugs are cost-effective and non-disruptive.. Unreliable evidence for drug treatments… GHG Some cases of OCD follow trauma … • Also, add Foe et al to your Psychopathology research bank. • What is a Randomized control trial? Ensure you can describe this type of experiment

32. Drug therapy is effective at tackling OCD symptoms • There is clear research to suggest that SSRIs are effective in reducing the severity of OCD symptoms (Soomro: 2009) Drugs are cost-effective and non-disruptive • Drug treatments are cheap in comparison to psychological treatments and, unlike psychotherapy, they are non-disruptive to patients’ lives Drugs can have side-effects • Although the use of drugs is effective for most, a significant minority receive no benefit and/or may suffer side-effects: weight gain, dry mouth, sexual dysfunction and loss of memory. Coming off a drug is a slow process in which the dosage has to be gradually reduced over a period of six months – risk of relapse.

33. Unreliable evidence for drug treatments • If drug companies sponsor the research they may decide to supress any results that do not support the drug they are marketing. Currently many drug companies do not publish all of their results and may indeed be supressing evidence.This suggests that the data on the effectiveness of drugs may not be trustworthy. Some cases of OCD follow trauma • Although OCD is widely believed to be biological in origin, it is also accepted that OCD can have different causes. There is a case for proposing that cases of OCD where there is no family history of OCD, but there is a relevant life event, should be treated differently from those where there is a family history and no trauma. It may be that for these cases drugs are not appropriate.

34. Can you…? • Explain the role of genes in OCD. (4 marks) • Explain two limitations of genetic explanations for OCD. (4 marks) • Outline the neural basis of OCD (4 marks) • Briefly describe one argument in favour of a neural basis to OCD. (2 marks) • Evaluate the biological approach to explaining OCD. (8 marks)

35. Essay Describe and evaluate the biological approach to explaining OCD (12 marks)

36. Essay Describe and evaluate the biological approach to the treatment of OCD (12 marks)