OCD-Biological approach and treatment Flashcards
The biological explanation for OCD focuses on genetic and neural explanations. What does the genetic explanation suggest?
The genetic explanation for OCD suggests that OCD is transmitted through specific genes and there is a biological basis for the disorder.
How are twin studies used to study the genetic basis of OCD?
Twin studies involve comparing monozygotic twins with dizygotic twins. Monozygotic twins have the exact same genetics and so if their probability of having OCD is higher than that of dizygotic twins then that implies a strong genetic influence. However, if the concordance rate is the other way around, there are implications for environmental factors.
Name a twin study supporting the genetic explanation of OCD.
Grootheest et al carried out a meta-analysis of over 70 years worth of twin studies and concluded that OCD has a strong genetic influence ranging 45-65% in children and 27-47% in adults.
Family studies can also be used to compare OCD sufferers to the general population. Briefly outline a study.
Nestadt et al found that children with first degree OCD relatives had an 11.7% chance of having OCD, compared to 2.7 of those that didn’t have first degree OCD relatives.
Genetics, such as the COMT and SERT genes affect serotonin and dopamine. Outline the role of the COMT gene.
The COMT gene regulates dopamine and causes higher levels of its’ production. It is more commonly found in sufferers of OCD thus implying that OCD has a link to high dopamine levels.
Genetics, such as the COMT and SERT gene affect serotonin and dopamine. Outline the role of the SERT gene.
The SERT gene affects the transportation of serotonin, causing lower levels of it. A mutation of the SERT gene has been found in two unrelated families that had 6/7 members suffering from the disorder.
Briefly evaluate the genetic explanation for OCD.
Uses twin and family studies which provide strong research evidence by showing high concordance rates for OCD compared to the general population, however, not all monozygotic twins share OCD, suggesting that environmental stressors may play a part.
How does the diathesis-stress model undermine the genetic explanation for OCD?
It combines genetic vulnerabilities with environmental factors thus explaining why monozygotic twins may not share OCD, thus undermining the genetic explanation.
Explain the major flaw with family studies.
Family members don’t display the same forms of OCD which suggests that the disorder is learned and not inherited. This explains that high concordance rates in family members are behaviours that are learned psychologically.
Neural explanations for OCD focus on serotonin and dopamine levels. Briefly outline two researchers’ findings regarding this.
Szechtman et al found that when dopamine increasing drugs were given to animals, their behaviours resembled OCD behaviours.
Pigott et al found that anti-depressant drugs reduce obsessive tendencies by increasing serotonin activity.
What is the link between OCD and serotonin?
Low levels of serotonin increase obsessive tendencies. Low levels of serotonin in OCD sufferers were shown using PET scans.
What is the link between OCD and dopamine?
High levels of dopamine increase obsessive tendencies.
What is the role of the orbito-frontal cortex in the brain?
The OFC is associated with higher-level thought processing and converting sensory information into thoughts.
What is the role of the basal ganglia in the brain?
Basal ganglia contains the caudate nucleus that is responsible for supressing OFC signals.
Comer linked dopamine to the frontal lobe. Outline his findings for the neural cause of OCD.
PET scans show that a damaged caudate nucleus in the basal ganglia fails to suppress worry signals to the thalamus that in turn signals the OFC thus making it a worry circuit.
