Psychopathology Flashcards
What two neurotransmitters is OCD thought to be related to?
Dopamine and Serotonin
What two genes have been linked to OCD?
COMT and SERT
How does the SERT stipulate OCD?
The SERT gene is responsible for producing an enzyme that helps transport serotonin and support’s the neurotransmitter’s function. The SERT gene can therefore inhibit the transport of serotonin, which results in lower levels of the neurotransmitter.
How does the COMT gene stipulate OCD?
Dopamine production is regulated by a gene called the COMT gene (as this gene gene controls the production of a specific enzyme that breaks down dopamine). A variation of this gene has been found in OCD patients which produces lower levels of COMT, resulting in higher levels of dopamine.
`Name a study that linked OCD to dopamine levels
Szechtman et. al 1998
In this study, animals were given drugs to enhance levels of dopamine, and were then observed to show ritualistic, compulsive behaviors that we tend to stereotype with OCD.
How was the link between low serotonin and OCD discovered?
the link was found after observing that antidepressant drugs that enhance serotonin activity (e.g. SSRIs) have been shown to reduce OCD symptoms, whereas antidepressants that do not involve stimulating serotonin do not affect OCD symptoms.
What two brain areas can be used to explain OCD?
The Caudate Nucleus (found in the basal ganglia) and The orbitofrontal cortex (found in the frontal lobe)
What is the role of the orbitofrontal cortex?
Sends impulses to the thalamus if the person finds something worrying or threatening (which then usually triggers the sympathetic nervous system). Wh
What is the role of the Caudate Nucleus?
It normally suppresses impulses from the orbitofrontal cortex.
How can the Caudate nucleus affect OCD?
If the caudate nucleus becomes damaged, it will not suppress the “worry” impulses sent by orbitofrontal cortex properly, so fails to suppress unnecessary or irrational threat signals. This causes threat/worry impulses to be relayed back and forth between the orbitofrontal lobe and the thalamus, creating a worry circuit (this can create the feeling during OCD behaviors n which one can not stop the ritual, as the anxiety impulses are being ruminated continuously)
How was the of the involvement of the Orbitofrontal Cortex in OCD discovered?
PET scans showed heightened activity in the OFC, when people with OCD were presented with a stressor.
How does the function of the Caudate nucleus involve neurotransmitters?
As suggested by Comer 1998, serotonin supports the regular function of the caudate nuclei, so a lack of serotonin could stipulate underactivity of the Caudate Nucleus.
Name one study that shows the links between genetic and abnormal brain structures
Menzies et. al 2007
Describe the events in M_____s et. al
Menzies— He used MRI scans to gauge what brain regions are most active in a group of OCD sufferers, their immediate family and a control group of unrelated, healthy people. Both the OCD patients and their relatives showed reduced grey matter in the OFC.
How did P__ls and L___man suggests the key genes in OCD patients can relate to other disorders?
They believed bearers of this gene often showcased obsessive behavior. Thy suggested other disorders that involved these genes, such as Anorexia Nervosa and Autism.
What is the flow diagram for how the COMT gene can stipulate a symptom of OCD?
Low COMT activity ⇾⇾⇾⇾ Dopamine levels are too high ⇾⇾⇾⇾Orbitofrontal Cortex is overactive ⇾⇾⇾⇾ Hypervigilance (Anxiety) ⇾⇾⇾⇾ OBSESSIVE THOUGHTS
What is the flow diagram for how the SERT gene can stipulate a symptom of OCD?
SERT activity is too low ⇾⇾⇾⇾ Serotonin levels are too low ⇾⇾⇾⇾ Caudate Nucleus underactive ⇾⇾⇾⇾ cannot regulate “worry” impulses ⇾⇾⇾⇾ COMPULSIVE BEHAVIORS
What does diathesis stress mean?
Suggests that disorders are caused by a combination of biological and environmental factors
What does SSRI stand for?
Selection Serotonin Reuptake Inhibitors
What are the three most common SSRIs used in Britain?
Fluoxetine (prozac), Sertraline (zoloft), Citralopram
How do SSRIs work?
By blocking the re-uptake of serotonin, but does not inhibit any of the other processes. It blocks the re-uptake canals, which leads to a build up of serotonin in the synapses.
What is one positive of the use of SSRIs
They are very cheap (only £1.50 per month)
What are 4 negative side effects of SSRIs?
Lethargy, reduced mental speed, reduction of physical and sexual arousal and weight gain/increased appetite.
How are SSRIs similar to tricyclics?
They also block the re-uptake of serotonin, and have similar effects as SSRIs but are more powerful.
What are the two most common examples of Tricyclics?
Amitriptyline (Elavil)
Clomipramine (Anafranil)
How do Tricyclics work?
They block reuptake of both serotonin and noradrenaline (works as both the neurotransmitters are in the same family). The build up of serotonin allows better impulse control, while the build up of noradrenaline aids with obsessive thoughts (also helps with concentration issues caused by excess serotonin).
What is one positive of tricyclics?
They are more effective than SSRis and can help reduce the concentration side effects that SSRis cause. Therefore, they are often used in more severe cases of OCD.