OCD Flashcards
What is the concordance rate for OCD?
33% for MZ twins and 7% for DZ twins
What other disease is OCD linked to?
Tourette’s Syndrome, it’s thought to share the same genotype.
Not clear why in some cases Tourette’s manifest in childhood and OCD in adults.
Tell me the link between Pediatric Autoimmune Neuropsychiatric Disorder Associated w/ Steptococcus (PANDAS) and OCD…
PANDAS is a disease caused by an autoimmune reaction that damages the basal ganglia (caudate in particular) and OCD and/or TICS can develop following the strep infection.
What do fMRI images show of brain activity in ppl w/ OCD?
Increased activation of orbitofrontal lobe and caudate
What has OCD surgical studies involving electrodes implanted in the caudate shown?
Increased activity in patients having obsessive thoughts during surgery and lower rate of activity in patients without obsessive thoughts.
Improvement in OCD symptoms is associated with…
Decreased activity of caudate and orbitofrontal area; durgs and beh therapy both produce this effect.
In severe cases of OCD, what does CINGULOTOMY do in psychosurgery?
Severs the cingulum, which connects the orbitofrontal and cingulate w/ limbic temporal lobe (hippocampus+amygdala)
In severe cases of OCD, what does CAPSULOTOMY do in psychosurgery?
Severs section of internal capsule connections between caudate and medial prefrontal.
When is psychosurgery for OCD performed and what’s the outcome?
Only in SEVERE cases when it can’t be treated any other way and 54% show definitely or probably improvement.
In psychosurgery w/ OCD, what happens to personality?
Negative personality changes are “very unlikely” w/ precision of modern surgery techniques. However, executive functioning deficits reported for some patients (planning, apathy, social disinhibition).
*man shot himself with a 22
How is deep brain stimulation used for OCD tx?
Electrode implanted in subthalamic nucleus & internal capsule associated w/ reduction in OCD symptoms in some treatment refractory patients
Whats the order for Brain Dysfunction in OCD (theory)?
1) The CAUDATE (learning and exec func)+PUTAMEN (regulate movmt and influence learning) receive input from entire cortex.
2) output thru 2 pathways to the THALAMUS (sleep & alertness) and FRONTAL LOBE (including prefrontal).
* Direct is excitatory
* indirect is inhibitory
What’s the theory for OCD in the output pathways (thalamus and frontal lobe pathways)?
The imbalance btwn these two pathways results in OVERACTIVATION of direct excitatory path.
Basal ganglia mediates what?
remember that cuaduate & putamen are in the Basal, motor fx
Execution of well-learned actions that are automatic so they can be executed rapidly.
Orbitofrontal area recognizes what?
Situations of personal significance and can activate the pathway and the behavior it controls (brain dysfunction OCD pathway)