Psychopatholgy - OCD Explanations And Treatments - Biological Flashcards
What’s OCD
- an obsessive compulsive, disorder leading to obsessive thoughts and compulsive behaviours
Obsessive thoughts - repetitive, depressing mental images or concerns causing anxiety
Compulsive behaviours - actions individual carries out as they feel they need to reduce anxiety
The genetic explanation
It is thought that a genetic vulnerability is inherited from parents
Analysis of genes has revealed over 230 candidate genes are more frequent in people w OCD
Many influence neural systems ie SERT - influences reputable of serotonin in the system
What other candidate genes are there ?
Gene 9, COMT and 5HT1-D beta gene
What does the finding of candidate genes make OCD
Polygenic - a predisposition to OCD requires a range of genetic changes
Evaluation - strength of evidence for OCD
- heritability evidence comes from fam and twin studies - general concordance in population is 2%
- however more gen related people show higher concordance - first degree relatives have 10% concordance and dizygotic twins have 31% concordance, mono - 68% concordance - suggesting OCD is inherited
The neural explanation can be divided into what ?
Biochemical causes ie neurotransmitter imbalance and neural structures
Neurotransmitter imbalance - serotonin
What process occurs too fast - explain and what gene is responsible for serotonin transportation ?
- low levels = obsessive thoughts and the low level is likely due to it being removed too quick from synapse before it’s been able to transmit a signal
- the process of re uptake: (release of NTS, binding to receptors on PS neuron, if signal is strong enough, message = passed on NTS detach and are taken back into pre s neuron) - happens too quick
SERT gene = responsible for serotonin transportation in synapse
Neural Structures - what is the worry circuit
A set of brain structures including the orbitofrontal cortex, basal ganglia and thalamus
Communication is overactive in people with OCD
What is normal functioning like - basal ganglia
Basal ganglia filters out minor worries from the OFC but if area is hyperactive, small worries get to the thalamus which is passed to OFC forming a loop - recurring obsessive thoughts
What are compulsions - in relation to the loops?
Attempts to break the loop - gives temporary relief but the hyperactive basal ganglia soon resumes the loop
What other area of the cortex is linked to OCD - gyrus
Parahippocampal gyrus - responsible for regulating and processing unpleasant emotions and function in people with OCD is abnormal
Strength of the biological approach to explaining OCD - concordance
Nestadt - higher concordance between MZ(68%) than DZ (31%) -
MZ and DZ grow in similar environments like : food, upbringing , education etc
Suggests that additional shared DNA is responsible for the increase in concordance which highlights the fact that there must be a biological aspect to it.
Weakness of the approach - correlation ≠ causation
MZ twins may be treated more similarly because they look exactly the same in comparison to DZ twins.
The concordance rate is 68 not 100% which shoes that the explanation can not be entirely valid as this shows the cause of OCD is not purely genetic, so there must be more of a Role from the environment
Strength - PET scans
Several PET scans have shown hyperactivity in the OFC and caudate nucleus of people who have OCD both while scamming the brain at rest and when the symptoms are stimulate but there is an issue with neural evidence - it’s correlational. Researchers can’t be sure if hyperactivity is the CAUSE or BECAUSE of OCD
Treatment of OCD - DRUG THERAPY
Primary class of drugs used = antidepressants known as SSRIs ie Prozac
How do SSRIs work , what is the name short for
Selective serotonin re uptake inhibitors
- they inhibit the reputable process therefore serotonin is present in the synaptic cleft and continues to stimulate the post synaptic neuron. - normalises activity of the worry circuit ; decreasing anxiety
Downside of drug therapy - slow
What to do ?
SSRIs can take 3-4 months to reduce symptoms and for some are ineffective
Dosage can be increased or other treatments such as benzodiazepines (anti anxiety drugs)
Enhances GABA which slows the central NS and results in gen. relaxation
What are tricyclics and SNRIs
Drugs that work by ^ serotonin and noradrenaline - they work on multiple NTs - have more side effects
Strength of drug therapy - cost
Inexpensive
More convenient for patient in comparison to like CBT which requires more time and trained specialist
Health services are more LIKELY to provide drug therapy
Weakness - side effects
Many patients prefer CBT because drug therapy can have a range of side effects, a meta analysis found - nausea, headache and insomnia were most common
Drug therapy can take 4 months before patient experiences symptom reduction - leading to dependency
Weakness of drug therapy - temporary solution
Drugs therapies may only cover up symptoms of OCD not actually treat the cause. Argued that serotonin imbalance is a RESULT of OCD, not the cause. Means the origin of OCD may not be biological but instead due to trauma. Research has shows ppl over 50% of 265 Ps had a traumatic experience increasing severity of symptoms - suggest D therapy is only temporary and psych therapies addressing trauma may be better
