Bio Explanstions Flashcards
What percentage of people with OCD had at least one parent with the disorder according to Lewis (1936)?
37%
This study highlights the familial nature of OCD.
What percentage of people with OCD had a sibling who also had the disorder according to Lewis (1936)?
22%
This finding supports the idea that OCD runs in families.
What does it mean when it is said that OCD appears to run in families?
Biologically close family members have a higher probability of having OCD if one member has it
This suggests a genetic component to the disorder.
What was the concordance rate for monozygotic (MZ) twins found by Carey and Gottesman (1981)?
87%
This indicates a strong genetic influence on OCD.
What was the concordance rate for dizygotic (DZ) twins found by Carey and Gottesman (1981)?
47%
The lower rate compared to MZ twins suggests that genetics play a significant role.
What does a high concordance rate in MZ twins compared to DZ twins suggest?
OCD is likely one of the most heritable mental disorders
This indicates a strong genetic basis rather than environmental factors.
How many genes had been linked to OCD by 2013 according to Taylor?
230 genes
This number is likely much higher now, indicating the polygenic nature of OCD.
What type of disorder is OCD classified as based on genetic studies?
Polygenic disorder
This means multiple genes are involved in the disorder.
What gene is specifically mentioned as being linked to vulnerability to OCD and depression?
5-HTT gene
A mutation in this gene has been identified as significant.
What is the role of the DRD4 gene in relation to OCD?
Codes for D4 dopamine receptors
Imbalances in dopamine may contribute to vulnerability to OCD.
What allele of the DRD4 gene is suggested to protect against developing OCD?
Allele 2
This allele is less common in people with OCD.
What does the COMT gene code for?
An enzyme that breaks down dopamine
Lower activity of this enzyme is linked to OCD.
What is the relationship between the low activity allele of the COMT gene and OCD?
More common in people with OCD
This could lead to excess dopamine and increase vulnerability.
What family of genes is involved in the development of new synapses and linked to OCD?
SLITRKs
Specifically, SLITRK5 has been associated with the disorder.
What protein is associated with the SLITRK5 gene and is important for neural networks?
BDNF (Brain-Derived Neurotrophic Factor)
Decreased BDNF levels may lead to abnormal cognition and behavior.
True or False: The genetic explanation for OCD is solely based on environmental factors.
False
The evidence supports a significant genetic component.
What gene is associated with the imbalance of serotonin that may increase vulnerability to OCD?
5-HTT gene
What may increase vulnerability to OCD in relation to serotonin?
Irregularities associated with the transport of serotonin, abnormalities relating to receptors, or problems with enzymes such as MAO-A
What type of dopamine receptor abnormalities may increase vulnerability to OCD?
D4 dopamine receptors
What production-related factor may increase the risk of developing OCD?
Production of BDNF
What is one of the key symptoms of OCD?
Repetitive behaviour
Who conducted research on the effects of oxytocin on repetitive behaviour in ASD?
Hollander et al. (2003)
What treatment method for oxytocin was explored in Hollander et al.’s research?
Administered in nasal drops
What is the relationship between oxytocin levels and OCD symptoms according to Humble et al. (2013)?
Higher levels of oxytocin are associated with more severe OCD symptoms
What phenomenon may explain the relationship between oxytocin and OCD severity?
Upregulation
What is the effect of DNA methylation on gene expression?
Decreases gene expression, silencing or turning genes off
What gene is associated with oxytocin receptors and may be affected in people with OCD?
OXTR gene
Fill in the blank: Higher levels of oxytocin are associated with _______ in people with OCD.
more severe OCD symptoms
True or False: People with OCD generally have low levels of oxytocin.
False
What did the study in Brazil reveal about people with OCD and the OXTR gene?
Greater methylation of the OXTR gene
